Telescope for deep sky photography

For people new to astronomy who want to ask those questions that they were afraid to ask. Receive helpful answers here.
Golucky
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Telescope for deep sky photography

Post by Golucky »

Hi, I am new to astrophotography. I like what I saw in the deep sky photos sharing on clubsnap and I wanted to give the niche area a try.

I seek your recommendations and viewpoint.

I like the deep sky pictures and the Milky Way. They are beautiful. I would like to take pictures of them and this means I need to put together a kit. In your opinion, is the Nexstar 6se and 8 SE a good system for beginner like me? I am getting a DSLR to be modified. So the cam is no issue. Now I need to check out the scope.

The other option is the Orion system. What's your take? Thanks in advance.
Hardwarezone
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Re: Telescope for deep sky photography

Post by Hardwarezone »

The Nexstar SE are altazimuth mounts and slow focal ratio. Not suitable.
For your purpose you need an equatorial mount, they compensate for the rotation that is visible for extended period.
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cloud_cover
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Re: Telescope for deep sky photography

Post by cloud_cover »

Hello and welcome to the club!
For astrophotography, the most important factor is the mount. You need a decent quality Equatorial mount for any success at all. This is because the mount must track the stars very accurately as they move across the sky or you will end up with smudged pictures. Don't believe everything the marketing says - do ask around before you actually place down money on your chosen equipment.
Next is your telescope: Ideally it will be light, fast (a small f ratio) and relatively short (focal length). SCT designs such as the Celestron 6/8SE are poor choices in this respect because they are usually f/10 - this means you need very long exposures, in turn requiring a much more accurate mount. Since it has a long focal ratio, its focal length is also correspondingly long. This means any shaking or inaccuracies in the mount is thus magnified.
Generally a good choice to beginning astrophotography will be a smallish refractor (such as an 80mm) with a decent focal ratio of between 5-7. Other designs such as imaging newtonians are also good choices but newtonians require collimation and for photographic work, that can be exacting. If the budget is generous, then specifically designed astrographs such as the Takahashi FSQ85/FSQ106 or the Televue NP101/NP101is will provide the best ease of use, but they are expensive.
You may also want to consider using camera lenses! While they are not as well color corrected as the better astronomical telescopes (especially the cheaper ones), they have the advantage of mating directly with the camera hence are easy to use and are also available in much shorter focal lengths than telescopes. This allows wider field imaging
There are other designs of telescopes as well but they are generally much more expensive and also heavy requiring a sturdy (expensive) mount.
Have fun exploring the world of Astrophotography!
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orly_andico
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Re: Telescope for deep sky photography

Post by orly_andico »

As CC says, the mount is the most important thing. Prices of mounts can vary between extremes. It's a matter of setting your expectations. As with everything in life, perfection costs serious money.

I have been playing with this nice little mount, the Star Adventurer. 1700 MYR from Perseid in Malaysia. Note that the $600 only gets you the mount - the red thing - and no tripod. The scope is also not included. A Manfrotto 055 or similar can carry the Star Adventurer nicely. That's another $300 or so.

Image

I like it very much! (even though I also have a significantly larger, more precise, and spendier mount) the Star Adventurer with say a 200mm telephoto lens and DSLR will occupy you for a long time, since most deep sky objects are larger. So if you have a 70-200/2.8 lens or similar that will do. An 80mm telescope like the one in my photo above is about $600 USD give or take.

The iOptron ZEQ25 is also a nice entry-level option. $800 USD.

The problem with the super-precise mounts is that they weigh a lot (they also cost more). I almost never bring mine even to Bedok because the act of disassembling it, carrying the pieces to the lift and to the ground floor, putting them in the boot, re-assembling the whole thing at Bedok field, and then repeating the entire process 3 hours later, is a complete pain.

Whereas I can carry the Star Adventurer and its lens/camera (or small telescope) and tripod, in one hand.
Golucky
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Joined: Tue Aug 12, 2014 11:03 pm

Re: Telescope for deep sky photography

Post by Golucky »

Hardwarezone wrote:The Nexstar SE are altazimuth mounts and slow focal ratio. Not suitable.
For your purpose you need an equatorial mount, they compensate for the rotation that is visible for extended period.
Thanks. Will take note of the equatorial mount requirement. :)
Golucky
Posts: 6
Joined: Tue Aug 12, 2014 11:03 pm

Re: Telescope for deep sky photography

Post by Golucky »

cloud_cover wrote:Hello and welcome to the club!
For astrophotography, the most important factor is the mount. You need a decent quality Equatorial mount for any success at all. This is because the mount must track the stars very accurately as they move across the sky or you will end up with smudged pictures. Don't believe everything the marketing says - do ask around before you actually place down money on your chosen equipment.
Next is your telescope: Ideally it will be light, fast (a small f ratio) and relatively short (focal length). SCT designs such as the Celestron 6/8SE are poor choices in this respect because they are usually f/10 - this means you need very long exposures, in turn requiring a much more accurate mount. Since it has a long focal ratio, its focal length is also correspondingly long. This means any shaking or inaccuracies in the mount is thus magnified.
Generally a good choice to beginning astrophotography will be a smallish refractor (such as an 80mm) with a decent focal ratio of between 5-7. Other designs such as imaging newtonians are also good choices but newtonians require collimation and for photographic work, that can be exacting. If the budget is generous, then specifically designed astrographs such as the Takahashi FSQ85/FSQ106 or the Televue NP101/NP101is will provide the best ease of use, but they are expensive.
You may also want to consider using camera lenses! While they are not as well color corrected as the better astronomical telescopes (especially the cheaper ones), they have the advantage of mating directly with the camera hence are easy to use and are also available in much shorter focal lengths than telescopes. This allows wider field imaging
There are other designs of telescopes as well but they are generally much more expensive and also heavy requiring a sturdy (expensive) mount.
Have fun exploring the world of Astrophotography!
Thanks for sharing. Noted on the sturdy mount, fast telescope (small focal length and bigger aperture).
I was planning towards the basic astrophotography ( basic refers to those photos of Milky Way in sg, with a subject in the photo) before jumping into deep sky photography. And I have more questions.

Till now I have only tried two attempts on ETTR. Far from fantastic and the white glow near to the horizon is always there. Therefore I thought I should try stacking. I am thinking of getting a eos crop body and remove the IR filter.

Questions:
1. After removing the IR filter, do I need additional filters to bring in the colours and block out the lights pollution further? I saw the H Alpha and oxygen filters. But I am unsure if those filters are necessary to bring out the beautiful colours of the deep sky.

2. And as the setup is the eos lens and the cam only, the filters must be the clip on type? There is no special filters for normal eos lens right?

3. Is there any system requirement for the eos camera? I'm looking at the eos60 to get close as the eos 60Da. However I SW many beautiful photos attained by 500d/600d range of camera.

I loved the time lapse done by Justin Ng and like to give it a time ( far target but should start somewhere right?). Will the eos cam setup with eos lens such as 70-200mmf2.8 get the type of photos in justin Ng time lapses?

Thanks for your advise. :)
Golucky
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Joined: Tue Aug 12, 2014 11:03 pm

Re: Telescope for deep sky photography

Post by Golucky »

orly_andico wrote:As CC says, the mount is the most important thing. Prices of mounts can vary between extremes. It's a matter of setting your expectations. As with everything in life, perfection costs serious money.

I have been playing with this nice little mount, the Star Adventurer. 1700 MYR from Perseid in Malaysia. Note that the $600 only gets you the mount - the red thing - and no tripod. The scope is also not included. A Manfrotto 055 or similar can carry the Star Adventurer nicely. That's another $300 or so.

Image

I like it very much! (even though I also have a significantly larger, more precise, and spendier mount) the Star Adventurer with say a 200mm telephoto lens and DSLR will occupy you for a long time, since most deep sky objects are larger. So if you have a 70-200/2.8 lens or similar that will do. An 80mm telescope like the one in my photo above is about $600 USD give or take.

The iOptron ZEQ25 is also a nice entry-level option. $800 USD.

The problem with the super-precise mounts is that they weigh a lot (they also cost more). I almost never bring mine even to Bedok because the act of disassembling it, carrying the pieces to the lift and to the ground floor, putting them in the boot, re-assembling the whole thing at Bedok field, and then repeating the entire process 3 hours later, is a complete pain.

Whereas I can carry the Star Adventurer and its lens/camera (or small telescope) and tripod, in one hand.
Thanks for your sharing. Perhaps I should try your setup before getting a scope. My questions on the DSLR+lens setup is about the filters. Any advise? Thanks in advance! :P
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Sivakis
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Re: Telescope for deep sky photography

Post by Sivakis »

AP can definitely be done with just an EOS and lens, especially when starting out.

The 60D is a good camera but do bear in mind of the weight of the camera. Initially this won't be an issue if you're just using cam+lens on a static tripod. But when you start mounting it on a telescope, the weight of the 60D starts to be a consideration, especially if the telescope is light. Which is also why many DSLR APers still go with the Rebel (XXXD or even 1000D/1100D) route. That doesn't mean the 60D can't do it cos it definitely can.

For the Milky Way, you'll want a wide lens. For starters, your DSLR may come with a basic kit-lens of either 18-55, 18-135 or 18-200 or any variant. That's a good place to start. Here are some of my starting settings when I first tried it out:
1. Set camera to Manual (M mode)
2. Shutter depends on focal length (I use the formula 400/focal length to determine)
3. Set aperture to around 800 or 1600 for starters
4. Use the remote timer (2 secs) or a remote shutter release if you have
4a. Alternatively, hook up your dslr to your laptop/pc and use EOS Utility to fire the camera
5. Turn the focus to infinity or near infinity to roughly get focus.
5a. Use the Live View function and Zoom in (5x or 10x) to finetune the focus
6. Fire away!

For the above, polar alignment isn't important, since the tripod is static and the shutter speed is calculated to minimise any star-trails from appearing.

I use Stellarium, a free program to get an idea of the stars that are on display. You can also search and read up on stacking software available. Most AP photos are a result of multiple shots stacked and combined together to capture and enhance the light photons captured per shot. I'm currently using DeepSkyStacker - which, in itself, is another journey in using and learning.

Once you move to longer exposure AP, then polar alignment becomes critical since you want to move beyond the shutter limitations in Step 2 above. Minimising vibrations and movement errors also become another consideration.

I definitely agree on the stability of the mount as most important when moving to the next stage. Some will say that a CG-5 GEM is the minimum but it also depends on the size and weight of the telescope. E.g. I'm using a CG-4 GEM but because my telescope is an Astrotech AT66ED which weighs only 1.8kg, it's sturdy enough for me. Mounts are expensive in SG (or at least, to me) but even then, when I shipped my CG4 from overseas, the shipping almost killed me! So you have been warned.

AP is a long dark road that's daunting and challenging. I'm still a beginner in every sense and learning as I go along but once you get a taste of what you can do...... then that's it. Hook, line and sinker!

Good luck and have fun in your journey!

EDIT: You don't necessarily need any filters to start on AP. Also note that if you buy a clip-on filter and put it into your DSLR, you cannot attached EF-S lenses to it. This is important unless you are only using EF lenses. (Just in case you're not aware, the 60D is an EF-S camera). Filters are there to reduce light pollution, enhance colours etc but does not mean you can't capture nice pics without it. Try it out first, especially if you already have a camera system. If you don't like it, it wouldn't have cost you anything! :)
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orly_andico
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Re: Telescope for deep sky photography

Post by orly_andico »

You can buy a 2" IDAS LPS-P2 filter. This has 48mm filter threads.

Then you can screw it into the front of your lens but you'd need step-down rings.

For example the Canon 70-200/2.8 has a 77mm filter diameter. If you put enough step down rings to mount the LPS-P2 to the front, your aperture has been cut down and it's not f/2.8 anymore but more like f/4.2 which is a royal waste of that expensive aperture.

The other option is the clip-in filter. But as the previous poster has stated, EF-S lenses can't be used (I particularly like my 10-22).

The light pollution really can't be gotten rid of without a filter.

The IDAS LPS-V4 is too harsh for a DSLR (it cuts off too much light). The H-alpha and O-III are even worse. To use an H-a filter with a DSLR requires an IR-modded one and long (e.g. 5-10 minute) exposures, which are not doable unless the DSLR is also cooled. So it gets complicated.

I'd stick with the LPS-P2 (maybe a clip-in) and EOS lenses. There aren't any fast and long EF-S lenses anyway so the EF-only requirement shouldn't be an issue.
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orly_andico
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Re: Telescope for deep sky photography

Post by orly_andico »

.. and regarding shipping mounts, this is why I love the Star Adventurer!

because you can buy it in Malaysia. http://www.perseid.com.my/star-adventurer-mount.html

Although, they are in Penang. Maybe you got relatives there. Or, go have a short vacation there. It's a long bus ride though (or a short plane ride).

If you go to one of the resorts in Penang, it is also dark and you can use your mount right away (don't forget to bring a tripod with 3/8" tripod screw). The Star Adventurer uses 4x AA batteries, even alkalines work fine.

The Star Adventurer has a bigger worm wheel than the CG4 or Vixen Polaris. And mine is measured at 30" periodic error. Not amazing (my other mount is... 2.8" periodic error) but for something so portable and (relatively) inexpensive, it's fantastic.
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