|
Post by Dragon Man on Mar 17, 2019 4:36:31 GMT
We all have our favourite Telescope for doing our Video Astronomy, but sometimes we may have 2 or more particular favourites. But it's not only restricted to the Telescope. We must also consider which Telescope works better with different filters, or CCD vs CMOS sensors, sensor size, object, etc. Suddenly, by simply changing filters, we fall in love with a Telescope we had almost relegated to the scrap heap. Now which one is your favourite As an example, I mostly use an ED80 with an IMX224 camera, a 0.75x Focal Reducer and an IR/UV cut filter. - Lovely resultsMy second favourite is a 6" f5 Achromat with an IMX178 camera, a 0.7 Telecompressor, IR/UV cut filter and a Minus Violet filter. - Fair to average resultsSo, last night I decided to do a bit of Focal Reducer and filter changing. In the ED80 I removed the 0.75x FR and used a 0.5x FR - Still Lovely resultsIn the 6" Achromat I removed the IR/UV cut filter and replaced it with an IR cut filter, and totally removed the Minus Violet filter. - AWESOME!!!The 6" f5 Achromat has now moved from being 'ordinary' to 'spectacular'. By swapping the IR/UV for a simple UV filter the green cast on stars has gone, and by removing the Minus Violet filter I am no longer blocking wanted Galaxy light. There is however a compromise: Galaxies look absolutely stunning (because all UV can now get through) but Emission Nebula is Green/Blue and Reflection Nebula is almost invisible. This has become an incredible Galaxy Setup, but a terrible Nebula Setup. The slight change with the ED80 has made no difference except for a slightly wider Field of View. It is still fair on Galaxies but spectacular on Nebula as they always were! Here's a couple of Examples from last night to show the difference. All Images are of different exposure lengths but all are stacks of 3. First is the difference in a Galaxy: M83 in the ED80 followed by M83 in the 6" Achro ED80 6" f5 Achro Where the ED80 excels: Trifid in beautiful colours Where the 6" now excels: Sombrero Galaxy So the point of all this is by testing different filters, Focal reduction amounts, camera/scope combinations etc, you may discover that a mediocre scope may end up your favourite scope Well, on certain objects, but not on others. Happy Experimenting! One last one: Table of Scorpius with the 6" f5 I love the star colours.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 17, 2019 5:57:13 GMT
I love your sombrero and M83. Thats what I am aiming for...plenty of structure in the galaxies. The colour is secondary in my mind. I havent experimented much with filters. Thats the next task. cheers Paul
|
|
|
Post by Dragon Man on Mar 18, 2019 16:39:58 GMT
This is the setup I used for the photos above
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 19, 2019 5:56:49 GMT
Ken, what is your Revolution R12 attached to? I am trying to find jobs for my mallincams. cheers Paul
|
|
|
Post by Dragon Man on Mar 19, 2019 6:57:19 GMT
Paul, I use a simple 'C' mount 6-60mm Zoom Lens from OC Telescope (Revolution Imager). There's plenty available on Ebay or you can get one from Mike at OC Telescope: HEREAny 'C' mount lens will work. I use that camera and lens as a widefield Finderscope, displayed on a seperate small monitor. See here in this pic,
|
|
elpajare
Member
Posts: 438
home town/country: Girona-Spain
time zone gmt +/-: 1
|
Post by elpajare on Mar 20, 2019 7:57:58 GMT
I like your control center, it seems comfortable and hot
|
|
|
Post by Dragon Man on Mar 20, 2019 15:30:41 GMT
I like your control center, it seems comfortable and hot Thanks Carlos. It's beautifully warm in cold weather and cool on hot nights. It is extremely well insulated You can see how much insulation went into it in the construction photos of our Observatory website HERE
|
|
elpajare
Member
Posts: 438
home town/country: Girona-Spain
time zone gmt +/-: 1
|
Post by elpajare on Mar 20, 2019 16:22:48 GMT
A good team work. And an outstanding result
Congratulations to all!
|
|
|
Post by vondragonnoggin on Mar 21, 2019 2:03:48 GMT
Ken, I’m picking up a Skywatcher 6” F/5 on a Saturday. Same color as yours. My Astro Telescopes AT152 is v1 of that Kunming United Optics scope and weighs 11kg. The v2 and v3 versions weigh 8.5kg. I wanted a faster optic for use with my Night Vision devices and the Skywatcher hits all the right criteria for me in weight and speed. Probably sell off the F/5.9 AT152 eventually. I’m so close on the AT152 with reducer in getting a live view of the HH like a good Ha photo, but a little more speed or a little more aperture would get me there. I chose the lighter weight and speed to get me there vs larger aperture. Would like to keep all my scopes less than 18lbs.
I think I’ll get a clearer view of the pillars in the Eagle nebula too.
|
|
|
Post by Dragon Man on Mar 21, 2019 13:26:09 GMT
Good choice Von. The 6" f/5 really sucks in the light! And it gets all 100% of the 6" due to no central obstruction. Mine has an Astro-Physics 2.7" focuser on it. It is stronger for cameras, better quality, and the large 2.7" aperture reduces vignetting. The difference is amazing! It requires an adaptor ring to be machined up so the focuser mates up with the tube size.
I also use a 2.7" Astro-Physics 0.75x Telecompressor (Focal Reducer) giving me f/3.75
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 22, 2019 10:09:39 GMT
Ken, I have a cheapo skywatcher 120 F/5 achromat that gets poor reviews for Astrophotography but I reckon it is not too bad for Videoastronomy. The stars certainly are blue bloated, but it picks up the dim fuzzies pretty well especially with some focal reduction. What filters do you reckon I should use for galaxies . cheers Paul
|
|
|
Post by Dragon Man on Mar 23, 2019 3:16:59 GMT
Ken, I have a cheapo skywatcher 120 F/5 achromat that gets poor reviews for Astrophotography but I reckon it is not too bad for Videoastronomy. The stars certainly are blue bloated, but it picks up the dim fuzzies pretty well especially with some focal reduction. What filters do you reckon I should use for galaxies . cheers Paul Paul, I can understand Astrophotographers giving bad reviews on Achromats. Many of them do so, without ever using one! But fortunately many also enjoy using them for AP. Yes, the Skywatcher (Orion, Saxon, etc etc) 120mm f/5 Achro is very good for Video Astronomy. That's why I have one Another club member, Tim, (I think you might remember him), likes mine so much he bought the same one. As to getting them to work well, if using a CMOS sensor, all you need to do is remove all filters you are using with it and only use a Bintel IR Block filter. Unfortunately Bintel have stopped selling their own branded IR block filter and the bad news is that even though it is just a re-branded GSO IR Block filter they are becoming rare Here's one on ebay: HERE
Agena also has them: HEREMake sure you don't get an IR/UV block filter. GSO and many others have a gazillion of them, but they don't work great for our purposes with our cameras in fast Achromats. If you really struggle to find a Bintel or GSO IR block filter you could try another brand but make sure it is only IR cut and NOT IR/UV cut. With all my experimentation I have discovered that the GSO/Bintel version has the spectrum cut-off point at the exact spot needed in a fast achromat. Other brands, while they are better quality are suited more for different exotic glass, they give strange colours in Achromats. A green cast to everything is common. It is also a different story when using a CCD sensor. But also be aware, while this filter brings out fantastic detail and colour in Galaxies and starfields (Star colours are magnificent!!) it turns all Nebulae into shades of green and purples As the saying goes, 'No scope does it all'. In this case, no filter fixes it all either
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 23, 2019 7:22:57 GMT
Yes, the Skywatcher (Orion, Saxon, etc etc) 120mm f/5 Achro is very good for Video Astronomy. That's why I have one Another club member, Tim, (I think you might remember him), likes mine so much he bought the same one. As to getting them to work well, if using a CMOS sensor, all you need to do is remove all filters you are using with it and only use a Bintel IR Block filter. Unfortunately Bintel have stopped selling their own branded IR block filter and the bad news is that even though it is just a re-branded GSO IR Block filter they are becoming rare Make sure you don't get an IR/UV block filter. GSO and many others have a gazillion of them, but they don't work great for our purposes with our cameras in fast Achromats. If you really struggle to find a Bintel or GSO IR block filter you could try another brand but make sure it is only IR cut and NOT IR/UV cut. With all my experimentation I have discovered that the GSO/Bintel version has the spectrum cut-off point at the exact spot needed in a fast achromat. Other brands, while they are better quality are suited more for different exotic glass, they give strange colours in Achromats. A green cast to everything is common. It is also a different story when using a CCD sensor. But also be aware, while this filter brings out fantastic detail and colour in Galaxies and starfields (Star colours are magnificent!!) it turns all Nebulae into shades of green and purples As the saying goes, 'No scope does it all'. In this case, no filter fixes it all either Thanks Ken,that answered the question. I try not to use filters if I can help it. I have a Mallincam IR cut filter. I notice they dont list them anymore. I presume it doesnt cut out UV as well. I have a few uv/ir cut filters ,a Baader and some no name cheapos . Bintel sells a ZWO 2" IR cut filter for $79. That's probably worth my while getting for galaxies It seems to me on any one night of viewing,if I have limited time, I need to decide what I want to capture - galaxies or nebulae. Pretty pictures or structure detail. The setups are very different There is still that unanswered question as to why CA is less in my cameras that have more pixels i.e. 294 and 178 than the 290 and 224 cheers Paul
|
|
|
Post by Dragon Man on Mar 23, 2019 9:45:50 GMT
Paul, give the Mally IR cut filter a try. You've got nothing to lose by testing it. I can't be 100% positive but I think the Mally filter is also a re-branded GSO IR block filter. It doesn't cut UV. UV light needs to get through to our sensors as most of the light from activity in Galaxies is in the UV (Stellar Nurseries, young hot stars, etc). All that lovely faint detail. As for 'galaxies' or 'nebula', that's why I run 2 scopes with 2 cameras simultaneously. I simply switch between the two in the capture software depending on what I want to look at. The ED80 does beautiful Nebulae, but tough for galaxies. Visa-Versa for the f/5 Achro.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 23, 2019 10:45:16 GMT
Thanks Ken Some of us are a bit slow on the uptake. I have a range of scopes ,cameras and filters. It has just clicked that I need a couple of setups. cheers Paul
|
|
|
Post by Dragon Man on Mar 23, 2019 11:24:02 GMT
Paul, piggy-back 2 scopes together and switch back and forth between them
I actually use 3 scopes and cameras together. My Guidescope makes a great widefield camera/scope and it also has an IMX224 in it.
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 23, 2019 13:09:39 GMT
I did have a st80 piggybacked on the Lx90 with a mallincam on each . It used to annoy me that the st80 got me better images than the lx90. I will have to rethink the setup.
No wonder I get confused cheers Paul
|
|
|
Post by Dragon Man on Mar 24, 2019 3:42:06 GMT
No wonder I get confused cheers Paul Bendigo Telescope Shop
|
|
Deleted
Deleted Member
Posts: 0
|
Post by Deleted on Mar 30, 2019 0:01:17 GMT
Ken said on March 17
Make sure you don't get an IR/UV block filter. GSO and many others have a gazillion of them, but they don't work great for our purposes with our cameras in fast Achromats. If you really struggle to find a Bintel or GSO IR block filter you could try another brand but make sure it is only IR cut and NOT IR/UV cut.
With all my experimentation I have discovered that the GSO/Bintel version has the spectrum cut-off point at the exact spot needed in a fast achromat. Other brands, while they are better quality are suited more for different exotic glass, they give strange colours in Achromats. A green cast to everything is common. It is also a different story when using a CCD sensor.
Ken,that is good information about the GSO IR cut filters . The Agena Astro site makes comment "GSO does not claim that this filter also blocks out UV wavelengths." So you are left not quite sure. I bought a ZWO IR cut filter only to find that it is actually a UV/IR cut filter. I should have looked at the chart. The Astronomik IR cut lets a lot of UV through and provides a chart but it is a lot more expensive than the GSO.
Weather has been cloudy here for more than a week and has now turned cold. At least the mozzies might give it a rest. cheers Paul
|
|
|
Post by Dragon Man on Mar 30, 2019 12:30:56 GMT
The Agena Astro site makes comment "GSO does not claim that this filter also blocks out UV wavelengths." So you are left not quite sure. Weather has been cloudy here for more than a week and has now turned cold. At least the mozzies might give it a rest. cheers Paul Paul, that is actually a good thing that Agena/GSO claim. We don't want it blocking out UV. We WANT the UV That comment would be made so when Astrophotographers suddenly find their images flooded with UV they can't angrily say " your filter lets UV through and ruined my images!" Agena can say "we warned you". If the GSO one end up disappearing altogether I will probably end up getting the Astronomiks IR cut filter. I have their UV/IR cut filter and it is fantastic!!!! on CCD's and ED scopes Not so on CMOS and Achromats. It's finally raining here! Sounds weird but we need the rain. This drought is ridiculous. I don't mind missing a week or two of Astronomy if it will save more animals from this current cruel starvation death, and farmers crops. The Farmers are really doing it tough.
|
|