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Post by fondofchips on Aug 22, 2015 18:57:59 GMT
Problem with focusing, LYRA 102mm F11 refractor, Mallincam Extreme & MR5 reducer. When I use this combination on a bright star it only comes into rough focus with the focuser tube on the Lyra scope all the way out. (Mallincam & both parts of MR5 reducer). I have the MR5 reducer, 5mm & 10mm extension pieces for the Mallincam. I also have a 2” extension for the scope focuser tube, I have also tried to video the Moon in daylight today but again focusing seems to be the problem. All I get is a grey screen on the monitor. Options 1 Swop to the SW 200P newt, I have a Moonlite CR2 focuser on there and motorised control, it also has it’s own 2” focuser extension pieces. 2 Flip mirror may help? 3 Perhaps the Lyra 102mm F11 frac just isn’t the right scope for the job? Would I be better off with a Triplet refractor anyway from a colour point of view? I’m thinking of 110-130mm ED APO approx. F7? - like this one www.teleskop-express.de/shop/product_info.php/info/p6679_TS-PHOTOLINE-130-mm-f-7-Triplet-APO---FPL-53---2-5-inch-RPA-focuser.htmlAny help would be most appreciated. Cheers, Harry.
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Post by davy on Aug 22, 2015 20:45:05 GMT
HI HARRY,i have a copy of a sw 200mm newt and have the same problem,,not enough inward focus,,i ended up giving up on that idea,,, I Had enough money in the kitty to buy a skywatcher st102 refractor but I found I was still having focus issues,, my solution was to fit a 80mm extension tube to my focusser, this was replaced with a flip mirror,this was the best piece of kit I have bought..you attach a 6mm eye piece to one section and your camera to the other,i had to use a sw Barlow(with lens removed) to fit it in my focusser..I found the sw st102 has coma issues so I got the skywatcher ed80 this is the weapon of choice for most video astronomers ,,fast scope and brilliant optics this scope bats well above its price tag..add the sw focal reducer/field flatner and bingo you have the ideal scope for video.. in my honest opinion
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Post by davy on Aug 22, 2015 21:00:19 GMT
hi harry, great looking scope,great specs ect...heafty price,,,the thing that makes video astronomy very different from astrophotography is the camera..the cameras we use( 1/3 rd sensors)as an example is about equal to what you see with a 6mm eyepiece,,this is why I use a flip mirror in my set up, far easier and faster to set up focus.the camera is the key to it all(for basic viewing)it will make a cheap scope into a great scope,a great scope is made into a truly fantastic scope.. listen to what the other guys say about scopes before making up your mind, what I wiould say there are many things video can do what you need to work out is what direction you wish to take,,,dso,,lunar,,solar,,planetary,,meteor,fireball,,,most guys dabble in all,,knowing this the guys can help mould the equipment you have or will need without costing you a fortune,,, lot of us have been there and bought the tshirt..unfortunately lol...davy
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Post by fondofchips on Aug 22, 2015 21:10:34 GMT
Thanks for that information, I'm new to the video side of things. I was planning a scope upgrade anyway but I wanted to get some of the video camera learning curve out of the way before I did that so that I was not working with all new gear. I will try the newt as maybe the moonlite focuser will work better, this scope was used for imaging before I bought it. Forecast is for a couple of hours clear sky tomorrow night so I will put the newt back on the mount. I use a ST80 as a finder with that scope so I will have 2 scopes to try. One thing that impressed me was despite the focus issue I aligned my finderscope much better with the video camera, you can see both views (finder & monitor) at the same time. Thanks again. Harry.
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Post by Dragon Man on Aug 23, 2015 7:13:03 GMT
G'day Harry. First, let me say that the focal lengths you are working with are very long. Not great for video. People often think that an f4 scope will give them fast optics which means a nice close up view of an object. But that isn't necessarily the case. With Video Astronomy we have to learn to ignore the focal ratio number, and concentrate on Focal LENGTH. The shorter the better. With Astrophotography the Focal Ratio is important. That is why many Astrophotographers try go as big as possible in aperture as long as it is between f4 or f8. But Video needs 'FASTER" optics. The way to achieve faster optics is to shorten the focal length regardless of the focal ratio. This is achived by two methods. 1 - A short scope - 400mm - 700mm or 2 - a Focal Reducer that will create a shorter focal length from a longer focal length scope. The best option is both together. A short scope PLUS a focal reducer. As an example, your f4 Newt is 1000mm long. You need to get it down to around 400mm with means super heavy focal reduction which come with Vignetting and coma and not a great quality of view, and that is if it's possible to get the Newt to focus! To make matters even worse, your refractor is 1122mm focal length!! The Apo you want to buy is f/7 which would be OK in a smaller scope, but when you start going up in aperture so does the length go up. Long Focal lengths will work (to a point) if you don't mind objects appearing very large, and faint. The disadvantages of slower optics are: smaller FOV, fainter objects, longer integrations needed, harder to locate objects, hard to focus, loss of sharpness, etc. The advantages of faster optics length are: wider FOV, brighter objects, short integrations, sharper focus, no need to sharpen the view in software, easier to locate objects, and you can fit in large objects. Many common objects like M42 are 1 degree across. That is a good target to reach. A 1 degree FOV will give you a really pleasing, brighter, sharper, quicker FOV for most objects. davy is correct, the good old ED80 is a fantastic scope for Video. But can be a bit hard in heavily light polluted skies. I use one and love it. I have been compiling live view results from different scopes with a Mallincam Xtreme. So far I have done ED80, ED100, 120mm Achro, 6" Achro, and a Meade SN10 ballaratman.wix.com/mallincamI am about to start doing the same thing with a Mallincam Xterminator. The images I have posted are all LIVE screen grabs so you can see the FOV and brightness and sharpness of objects in these scopes. Back to the scope you are considering, that is a hefty price! Just to let you know what your options are, when you look through my images from different scopes, notice that the 120mm and the 6" are Achromats which usually give terrible results with CCD sensors. They suffer Chromatic Aberration and false colour like this: But I use a Wratten #12 Yellow filter which completely eliminates the problem like this: (the images on the right are with the yellow filter) and that shows that you can achieve almost Apo like results with a Achro scope costing around 1/4 the price, maybe even less. Also because it is an Achro you will need an IR filter. That stops the stars from going blurry. here is the difference with and without an IR filter: (it is a 2 frame animation so please wait for it to load) That should give you some things to think about If you have any further questions, I'm happy to help where I can.
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Post by fondofchips on Aug 23, 2015 14:42:39 GMT
G'day Ken, Well your write up is more than I could have possibly hoped for, it looks like I'll be using my ST80 for now at least. I was planning an upgrade anyway before I decided to have a go at video astronomy. I just could not find enough info though, until I came across your videos, so I bought the Mallincam Extreme knowing already that I (probably) had the wrong scopes anyway. I like the idea of being in the warm in winter and seeing more than you can with an eyepiece. I decided not to do any more dark site work after building the obsy. So the frac & my mobile mount were due to be sold anyway, I've never got on with the Newt either, so my plan was selling up and buying one really decent scope. It is summer here in the UK, (it's raining or course) so it's a buyers market for astro stuff so I'm leaving the selling to nearer the winter.
On your recommendation of shorter focal length the the William Optics FLT 110 is the best scope I've looked at (so far) and there are a few secondhand ones around at the moment. Spec - William Optics FLT 110 DDG APO Triplet Focal length 770mm 2 speed 3.5" Crayford focuser F - ratio F7. All the others on my short list have a longer focal length than that one.
It's back to the drawing board then as I obviously have much more homework to do before changing my scope.
Light pollution wise I live in a town with a bigger town to the West of me, my views to the South & East are good, I do need to tackle the light pollution, but it is not as bad as a city would be. I would not have built the obsy if the LP was really bad anyway.
Thanks again for your help
Cheers, Harry.
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Post by Deleted on Aug 23, 2015 16:07:14 GMT
Hi Harry, The 110mm WO is a great scope for video, I use one with good results. Most of the time I use it at f7 on smaller to medium size objects. On a AVX mount it is a perfect match. On large targets I use a AVS varioreducer at .63, .48, .38, or as low as .26. I find best results are at native 770mm in most cases though, better sampling. I have used a ASI 120mc, AVS DSO, and Lodestar X2 color and mono in it along with a dslr. I do use a 75mm extension tube at times as I don't like using a diagonal except near the zenith, when I'm in danger of hitting tripod leg. Richard
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Post by fondofchips on Aug 24, 2015 8:28:31 GMT
Hi Richard,
Thanks for the information, I have revised my short list on Ken's recommendations, it is going to be a bit strange with a small scope on the mount.
Clear Skies, Harry.
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Post by Dragon Man on Aug 24, 2015 9:27:08 GMT
Smallish scopes on Big mounts. Perfect combination. The opposite is a horrendous situation
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Post by fondofchips on Aug 24, 2015 9:44:45 GMT
Dear Ken, After reading your recommendations this is my revised scope short list. Altair Wave Series 80mm F6 Super ED Triplet APO 80mm focal length 480mm Skywatcher Esprit 80 ED PRO Triplet 80mm focal length 400mm Skywatcher Esprit 100 ED PRO Triplet 100mm focal length 550mm William Optics FLT 98 APO Triplet 98mm focal length 618mm William Optics GT-81 Triplet Refractor 81mm focal length 478mm I can buy the William Optics FLT 98 with the WO Flattener/reducer - the reducer is included at the scope price - www.williamoptics.com/accessories/flattener4_features.phpThe description here talks about DSLR sensor sizes, how does that compare to the Mallincam Extreme? The other one that looks good is the Skywatcher Esprit 100 ED - I'm thinking that a little more aperture would help if I have to use filters for light pollution. No problems with weight as I have a SW AZ-EQ6 GT mount and I'm obsy based. Tried the SW 200P Newt with the Mallincam last night, nice views of the moon & bright stars are sharper, buts that's all, then it dewed up.... Thanks for your help. Cheers, Harry.
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Post by Dragon Man on Aug 24, 2015 14:46:32 GMT
Harry, I can't speak for the Reducer that is included with the WO FLT98 as I've never used one of those type of reducers. Maybe someone who has used a 0.8x reducer could chime in and help. 0.8x is very mild reduction. But all the scopes you list would be fantastic. Native and Focally reduced. If I had the $$$ my choice would probably be the Skywatcher Esprit 100 ED PRO Triplet 100mm focal length 550mm I did make a tutorial on how to make your own focal reducer
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Post by Rick in NWArk on Aug 24, 2015 14:55:16 GMT
Early on I thought I would be doing Astrophotography and Video Astronomy... hahaha. Astrophotography, if done right, requires your full attention. I get so many more results with Video that I have shelved my Astrophotography ambitions for now.
To that end, I have been focusing on getting my scope collections right. I started off with the Mallincam VRC8, an 8" Ritchie Critien (native 1624mm focal length and f/8). I got off to a good start, but had some significant mount issues. I got a great deal on an Orion 80EDT triplet APO and I've actually used that scope more than the VRC8. That scope is native 480mm and f/6. So very easy to get wide fields and sub-f/4. I'll say even the F/6 is not bad when my mount is properly aligned and tracking.
I've recently picked up the Explore Scientific AR-152 (native 988mm focal length at f/6.5) which although an achromatic has excellent reviews. I'm anxious for its first light.
These different focal lengths gives me a good combination of image scale (from the focal length) and brightness (focal length plus camera exposure / gain).
At the end of the day, there is no perfect scope that can do everything great... its all about deciding what you are going to spend the most time doing and maximizing your results for that.
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Post by fondofchips on Aug 24, 2015 17:14:58 GMT
Dear Rick, Thanks for the information, the ES AR-152 scope looks to be very good value. If you want a scope to do more than one task there is always a compromise somewhere. I was going to update my scopes anyway so I wanted to be sure I was buying the right one.
I will be going for the Skywatcher Esprit 100 ED PRO Triplet as Ken recommends, neither of my existing scopes work with the Mallincam anyway.
Thanks again, Cheers, Harry.
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Post by Rick in NWArk on Aug 25, 2015 13:51:51 GMT
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Post by Dragon Man on Aug 26, 2015 6:01:22 GMT
As far as an extension tube, I use a GS 2" 2x Barlow with the Barlow lens removed. It simply screws off One of these: HERE
The main advantage of using a 2" extension tube over a 1.25" is the reduction of Vignetting that can be caused by a 1.25" extension tube. Plus the fact that I already had the 2" Barlow and don't use it The Barlow will accept either a 2" or 1.25" camera nose-piece.
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Post by fondofchips on Aug 26, 2015 8:07:02 GMT
G'day Rick and Ken, I have a spare 2" extension tube that came with the Moonlite focuser so I should be OK. Thanks for the information. Skywatcher had quality issues with the Esprit 100 ED PRO Triplet when it was first introduced so I'm going to e-mail the supplier before ordering it so I can be sure those issues have been sorted out. Thanks again, Cheers, Harry.
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Post by fondofchips on Aug 30, 2015 5:58:46 GMT
Dear Ken, Rick & Davy,
I've ordered the SW Esprit 100 ED PRO Triplet, should be here next Wednesday, I've also ordered a solar filter which should give me more practice time with the Mallincam Extreme. Thanks very much for all your help. Cheers, Harry.
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Post by davy on Aug 30, 2015 10:09:36 GMT
hi harry fantastic scope(jelous you will deffo get some fantastic images from that bad boy lol.. rigged up to the mallincam..deffo the wow factor.. i see you have your old kit up for sale in the sgl classifieds, any of my older kit i just cant push myself to get rid of it..davy
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Post by fondofchips on Aug 30, 2015 10:30:13 GMT
Dear Davy, I'm simply not going to use the 2 old scopes and the dosh will go towards the new one. After I built the obsy my stargazing completely changed, I don't want to do dark site work anymore so the Lyra frac & the EQ5 can go. The SW 200P does not work with the Mallincam except for lunar work. I have split it down as the Moonlite focuser on it's own is worth over half the value of the scope. It is a bit early in the season to expect stuff to sell quickly anyway. First job with the Esprit will be to work out which are the best eyepieces for it and wittle that down to 3 or 4, the rest will be sold again to raise some dosh. I have a ST80 & decent tripod for mobile work. I'm going to miss the Lyra scope it has always performed very well but it is no good gathering dust and someone else will enjoy it. The best ever experience was with Uranus using my Nagler 2-4mm zoom, at 2mm Uranus came into view, I'm told that's around 500x which really tells how good that scope is. It suffers from some CA on bright objects of course but value for money wise it is brilliant.
The new scope is intended as a long term purchase so when I've sorted out what I need the serious stargazing will begin.
Thanks for your help, Cheers, Harry.
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Post by Dragon Man on Aug 31, 2015 14:25:04 GMT
Harry, not having a dig at you, just making an observation, but you don't need to make your posts formal with 'Dear Davy' or 'Dear' anyone at the start of each post The idea with Forums is it is a conversation like you would have standing next to each other. Forums are very informal
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