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Post by fourowls on Jan 19, 2018 21:48:16 GMT
Howdy everyone! Sorry if this has been covered or that I haven't found this out myself yet, but can I use a 10 or 12" DOB with GOTO with good results for video astronomy (say using a GSTar - EX4 or Revolution camera...etc)? I am just used to dobs and have never had any other kind. However I am open to telescope suggestions for scopes that would be great for V.A...so drop me a line please! I can get a Celestron Nexstar 8se or 6se at not bad second hand prices or whatever.... If a Dob is okay any camera suggestions that would be best for this type of scope? Thanks in advance! Regards Andrew H
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Post by davy on Jan 19, 2018 22:59:29 GMT
Welcome to the forum Good news bad news scenario Yip you can use a goto dob for various,, but has limitations . But there are ways round it,, stacking short exposure captures ect,, really depends on what type of various you want to do...solar,lunar,planetary,deep sky.. knowing this we can then guide you more to the other bits of kit to achieve your goal. I.e focal reducer to speed up your scope What type of camera/sensor size As usual no one scope does it all..
Flexibility is the name of the game Personally I believe a good eq mount is the way to go,,I use a heq5 and although I would like a bigger mount this works for me,, to me mount is the most important part of our kit.
Scope wise ,,I use three,, skywatcher explorer 200pds, skywatcher ed80 with matched focal reducer and skywatcher st102... I have a dual saddle kit so can do combo of the scopes. Few cameras canon 600d cameras,,modded canon 450d,,qhy5lii colour guide cam Orion finder guider Zwo asi168mc I use various techniques for captures.. Working on pc stick controlled scope at moment
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Post by fourowls on Jan 20, 2018 0:50:07 GMT
Hi Davy
Thanks for taking the time to respond to me and yes I guessed it, there is no one perfect scope!! To be honest I want the V.A for deepsky and objects that are hard or impossible for my visual observing to see. If this includes certain nebs or galaxies but from what I have read, V.A can really bring out details we can't see due to some degree of stacking and time delay to build greater light (I am not being accurate in my description but hopefully you know what I mean!). So if a dob is no good then happy to look at something else as I can have a cheap 10" Dob just for visual stuff anyway and the brighter lunar/planetary stuff (I will keep that dob manual so I can keep on learning the night sky and only get used to tracking...). So yes,,,whatever deep sky stuff that a light polluted backyard won't see without V.A would interest me!!!
Regards and thanks!
Andrew H
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Post by Dragon Man on Jan 20, 2018 5:01:46 GMT
Andrew, there are several people around the world using reflector (dob) scopes for Video Astronomy. Also consider that there are several hundred, maybe a thousand, people worldwide doing Video Astronomy.
Several people out of hundreds tells you a lot about the success/struggle of using a dob.
They do work, but with huge limitations. The main one being focal length, another being focus. In general, reflectors have a long focal length which is not great for what we want to do. Fine for Visual, but we want to get the whole scopes Field of View onto a tiny sensor, so we need to use a Focal Reducer to make the object smaller (the FOV wider). Here's where Focus comes into it. Usually reflectors will not reach focus when using a Focal Reducer.
Some people modify there reflector, or just buy another scope with a shorter Focal Length. Some also like using SCT's but they too have very long Focal Lengths but a product is made to solve the problem. An expensive item called a 'Hyperstar' or 'Fastar'.
The alternative is a 3.3 Focal Reducer fitted to an SCT or a fast Refractor. Many Refractors do a great job. Even Achromats which are normally taboo for Astrophotography. I personally use Achromats more than my other scopes.
Stay away from 'Maksutovs'. They have ridiculously long focal lengths.
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Post by fourowls on Jan 20, 2018 6:44:54 GMT
Hi Ken! Good points and I now know that I will not be using a dob for V.A!! I am surprised that there are not more people doing V.A?? Is it that new? The benefits seem to be there and be able to see things that the naked eye can't is definitely one of them...although there are constraints. Okay well I am very grateful for the advice and will start the look around for a scope as I got rid of a lot of gear! Always fun to search! I can get hold of a Celestron 9.25" XLT (CST) scope but I will review your advice on this and the long focal length... Just a question if I can, now that you are into V.A would you ever go back to just visual? Does V.A spoil you a bit? LOL...anyway,,,onto scope searching and I if you're cool, I will put up scope suggestions I find for advice!!
Regards Andrew H
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Post by davy on Jan 20, 2018 7:23:17 GMT
Personally,, i think that visual observing you get a rich image from an eyepiece and this richness is what I would like to get from a va camera,,the camera seems to flatten the image in my mind,, but the beauty of va is deeper visual observing with the facility to save the capture,, va or EAA has so many variables for capture techniques it is getting more popular.
You can use Webcams Dslr with capture and stacking software Dedicated astronomy cameras and custom software And split it down again with analogue or digital cameras
colour or mono Narrowband ,lrgb imaging
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Post by davy on Jan 20, 2018 7:46:26 GMT
Scope wise I use the skywatcher ed80 with the skywatcher 0.85 matched focal reducer/flatner,, it's a great scope for the money and the focal reducer makes it better,, this is my va scope . But a nice fast quality lens on a dslr works great and Howie can dive in with info on his new lens.
The beauty of the telescope is being able to make it better by adding to it. A filter wheel for example Using various filters to improve either images Using different types of cameras , from smart phones at a lens to dslr types then of course the different astronomy cameras with the different sensors.
My kit is always changing till I find the best fit for me
I'm currently building my latest
Skywatcher heq5 pro with a skywatcher wifi to be controlled via a smart phone or laptop via ascom
Going with a single scope but will be using my twin scope saddle and add a second scope at a later date
Skywatcher ed80 and 0.85 matched focal reducer,, five position filter wheel with baader hydrogen alpha filter and oiii filter and add a hydrogen beta filter later,, moon filter and leave one blank
Zwo asi 178mc camera or canon 450d modded camera.
The scope will be modded to hold a PC stick and seven port usb hub and control my skywatcher focuser controlled by hitecastro usb focuser..
Will be controlled by main laptop wirelessly.
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Post by Dragon Man on Jan 20, 2018 11:47:40 GMT
Hi Ken! Good points and I now know that I will not be using a dob for V.A!! I am surprised that there are not more people doing V.A?? Is it that new? The benefits seem to be there and be able to see things that the naked eye can't is definitely one of them...although there are constraints. Okay well I am very grateful for the advice and will start the look around for a scope as I got rid of a lot of gear! Always fun to search! I can get hold of a Celestron 9.25" XLT (CST) scope but I will review your advice on this and the long focal length... Just a question if I can, now that you are into V.A would you ever go back to just visual? Does V.A spoil you a bit? LOL...anyway,,,onto scope searching and I if you're cool, I will put up scope suggestions I find for advice!! Regards Andrew H Andrew, I have been doing Video for 13 years. With sporadic spells of Astrophotography within those years. But, I still do Visual on Club nights so I can keep my eye in practice. I enjoy both Video and Visual. It's a big buzz seeing an object billion of light years away as it was billions of years ago with just my human eye! It's mind-boggling But there is also something special about seeing what normally appears as a featureless grey smudge through the eyepiece suddenly pop up on screen with detail and in full colour. Both are fun. By all means, ask about scopes. The C9.25 has a 2350mm focal length Wow that's long! Going to need some good Focal Reduction.
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Post by fourowls on Jan 20, 2018 21:57:02 GMT
Hi Ken!
Okay, yes that's right you had mentioned avoid long focal lengths so I will rethink that! I know this sounds stupid but as I have been firmly in the 'aperture is king' camp for a while it is still hard getting my head around a small aperture like 80mm, but yet when I saw Howie's or your own presentation of the results I was like, "How does something so small produce such great results of things that I can't see even with an 16" dob in my backyard?"....although my results may vary as I am in a brown/orange light pollution zone in the Brisbane/Gold Coast corridor. I really like the look of the 127 Explore Scientific Triplet but then it then needs a tracking mount and that adds up pretty quick,,,then the camera (man this hobby can separate a man from his dollars!!).
I have made a note of the Skywatcher ED80 as one on my list...I will let you know any more I find! There is an Explore Scientific ED80 (F/6 Triplet Refractor for about $900 or the 102 Doublet F/6.5 so I would need focal reducers but not as bad as the 9.25 SCT I saw....
Anyway thanks Ken for your replies!
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Post by Deleted on Jan 21, 2018 10:55:23 GMT
Andrew To use a big dob for VA you need a big sensor that is also sensitive enough so exposure is less than 20 secs. The 294 fits the bill but 20 secs is too short for the 1600. I add a .6 FR which takes the F5 to F3.9.
My favorite scope is the 6 sct with hyperstar but it requires a small sensor. I have an 8 Lx90 with optec 3.3 focal reducer but it is not as good as the hyperstar. The 3.3 reducer also needs a small sensor. If I had my time again I would buy a C8 with hyperstar which can handle large and small sensors.I think the right combination of gear is fine on alt /az with today's cameras.
Having said all that,I am waiting for my SW EQ6-R to arrive so I can put the 1600 to good use with my 10 Lx90 which has been very disappointing for VA. The 2500 FL needs very good focal reduction as Ken says. Without a lot of FR you need longer exposures and therefore an eq mount Paul
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Post by Dragon Man on Jan 21, 2018 11:17:54 GMT
You're welcome Andrew. We are here to help each other. The ES127 is great but can get expensive in Aussie Dollars. Here's a nice scope currently on sale: Long Perng 110mm f/6 QUADRUPLET APO ED OTA refractor with 11:1 Crayford style focuser A$1999 (But would also need Tube Rings and Dovetail plate)Go to the 'Long Perng' page here: www.andrewscom.com.au/optical-telescopesAnd pop it on a HEQ5 or NEQ6 Goto mount: HEQ5 NEQ6 for only $200 more!!! Go to the 'Skywatcher' page here for both mounts: www.andrewscom.com.au/optical-telescopesThat's $3500 for the Long Perng 110mm f/6 QUADRUPLET APO and an NEQ6 mount!!! That would have you set for life
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Post by Dragon Man on Jan 21, 2018 12:39:43 GMT
and still at the same website: www.andrewscom.com.au/optical-telescopes on the Skywatcher page is a better deal with IMAGING Newtonians with Mount included. Nothing else to buy. Comes mounted with Rings and Dovetail, finderscope, Eyepieces, 2" to 1.25" adaptor, extension tube etc. 8 inch 800mm focal length Imaging Newt on HEQ5: 8 inch 800mm focal length Imaging Newt on EQ6: Both good setups. But because I have never used one of Skywatchers 'Imaging' Newts I don't know if they can still reach focus with a Focal Reducer. I would guess yes, but it would be nice to get confirmation first. A 0.5x Focal Reducer at most would be preferred for many objects, so it would need to be able to reach focus with a 0.5x FR. If it reaches focus with a 0.5x FR then anything less will easily reach focus.
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Post by fourowls on Jan 21, 2018 12:53:02 GMT
Hi Ken
Brilliant and thanks kindly for your research and hard work! I will check into those! Actually I was looking at imaging Newts and was wondering about them too....they seem to combine best of both worlds but as you mention more confirmation is needed about the focusing issues! I will be following these through tomorrow and thinking carefully about what options I can get with my budget. On top of these I would need to add in a camera too (that is another question of which one to start with!!)!! Ahh the joys of it all!
Food for thought again Ken! Many thanks!
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Post by davy on Jan 21, 2018 12:57:50 GMT
and still at the same website: www.andrewscom.com.au/optical-telescopes on the Skywatcher page is a better deal with IMAGING Newtonians with Mount included. Nothing else to buy. Comes mounted with Rings and Dovetail, finderscope, Eyepieces, 2" to 1.25" adaptor, extension tube etc. 8 inch 800mm focal length Imaging Newt on HEQ5: 8 inch 800mm focal length Imaging Newt on EQ6: Both good setups. But because I have never used one of Skywatchers 'Imaging' Newts I don't know if they can still reach focus with a Focal Reducer. I would guess yes, but it would be nice to get confirmation first. A 0.5x Focal Reducer at most would be preferred for many objects, so it would need to be able to reach focus with a 0.5x FR. If it reaches focus with a 0.5x FR then anything less will easily reach focus. The skywatcher imaging newt is shorter to allow better focus,, the normal skywatcher 8" with dslr is minimal focus travel,,nearly a miss 😁,, would like the Quattro myself,, love the views from mine,, my moon scope lol
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Post by Deleted on Jan 21, 2018 16:04:30 GMT
The 8 inch 800mm focal length does reach focus fairly easily with a .6 FR but I havent used it much yet. One of this year's projects. i bought the 200 f/4 separatly from heq5 pro and the sw eq6-r which is a costly way to do it. Paul
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Post by ChrisV on Jan 21, 2018 22:00:39 GMT
Edit. Forget this post.
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Post by ChrisV on Jan 21, 2018 22:03:16 GMT
Those Long Perngs are a good price Ken. Wonder what they are like ?
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Post by howie1 on Jan 22, 2018 6:31:55 GMT
Andrew, Howie here ... I am in Brissie Bayside. Send me a pm and I'll come pick you up and we'll head out. I primarily use EQ with an 8" newtonian, but have also modded the struts on a 12" GoTo dob to do EAA. BTW, join up NSN (link at the top in this forum), and also join the NSN FB page to in particular see Mark George in NZ do live broadcasts. He uses a 10" GoTo DOB exclusively. He's piggybacked 80mm refractors as well as two Canon's with Canon lens all on the same rig. It's so overweight, he has made a custom counterweight on a slide mechanism to allow the ALT motor to actually work to move the scope (otherwise it simply hasnt the power to move it in ALT). Yes, AltAz limits to stacking 20 sec shots and in some cases longer, but that's what even the 224 sensored cameras do when in EQ. You can see posts in this forum all the time with 30 stacked 20 sec shots using Rising Tech and other cams. So no probs using Alt Az ... but if you don't own any scopes at all then I wouldnt buy AltAz as the first scope ... if you are serious about getting into VA / NRTOWC (Near Real Time Observing With Camera!) and dont own a scope then get an EQ mount. They are absolutely not hard to setup. The web is full of BS on that! LOL
Send a pm and we'll chat. cheers Howie
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Post by fourowls on Jan 22, 2018 7:11:41 GMT
Hi Howie
That's awesome and would love to see things first hand! I am sadly still very new and have only basic knowledge but I guess we all to start somewhere! If you're cool I would love to organize something and just let me know. I do admit I love dobs...but I have Scottish parents and therefore like bang for the buck perhaps? However I am more than prepared to take good advice when needed and this may sound blasphemous but doing hours of visual to just a see a grey smudge did admittedly get frustrating at times but if EAA/VA can provide a deeper window into the universe then I am definitely keen! I don't expect miracles but from the videos I have seen from members on this forum I am more than interested! (Just in the process of getting some more funds together but that won't take long and gives me time for research and proper thought into what I need).
I will check out the NSN and subscribe to that FB page of the gentleman in NZ. Yes I look into the EQ mounts and simply put effort into getting use to using them! I am trying to avoid the temptation of a nice 9.25 SCT scope that I can get for about $1800 that has GOTO but apparently the focal length causes issues as it is seriously slow. Okay drop me a line of a time you were thinking of going somewhere and I can meet you there as I don't need to cause you too much trouble, or I can come to your place or somewhere neutral! Another scope I like the look of are the Explore Scientific AR152, but by the time you put a mount on them,,,etc it gets too expensive. I do like the idea of a nice 10" newt on an EQ mount (despite the naysayers, but again I can take good advice!!). Looks like my expensive Gypsy Jazz handmade guitar is definitely up for sale!! lol!!
Regards Andrew H
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Post by ChrisV on Jan 22, 2018 11:18:31 GMT
I'd like to see a pic of that guitar!
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