Recommendation for small refractor for astrophotography

[Spider-Man]

Hi, I'm keen to buy a small good quality refractor primarily for astrophotography of galaxies and nebulae.   I'd like to use my Pentax K1 full frame DSLR with the telescope.

Reviewing YouTube & Google the; Altair Astro 72 EDF deluxe & William Optics 71GT look like they might be good models to go for.  I'd welcome the community's views on both, and any other alternatives people recommend.

[Floater]

Just read something about a new launch of StellaMira scopes that might fit the bill! 🙂 (See FLO post.)

[happy-kat]

Hi

Some galaxies are quite big so if you've any nice prime lenses I wouldn't rule them out.

What mount are you intending to used your gear on?

[vlaiv]

Using full frame sensor is going to be an issue as not many scopes are fully corrected for that format - especially smaller scopes.

Are you limited by your mount in some way (star adventurer or AZGti or similar?) - if not - look at 80-100mm range of refractors with good field flattener.

I have TS 80mm F/6 APO and it is indeed very nice little scope. With Riccardi reducer you will get nice F/4.5 scope and about 360mm FL - however, for imaging of galaxies I would choose something with a bit more oomph - maybe this scope:

https://www.teleskop-express.de/shop/product_info.php/info/p11871_NEU--TS-Optics-PHOTOLINE-115-mm-f-7-Triplet-Apo---2-5--RAP-focuser.html

I linked that one on purpose (there same model without discount price) - because I believe discount price is worth having since these are supposed to be showroom models at lower price. One of member recently purchased one and impressions were good (search the SGL - there is topic about it).

[Spider-Man]

1 hour ago, Floater said:

Just read something about a new launch of StellaMira scopes that might fit the bill! 🙂 (See FLO post.)

thanks, i'll check it out

[Spider-Man]

47 minutes ago, vlaiv said:

Using full frame sensor is going to be an issue as not many scopes are fully corrected for that format - especially smaller scopes.

Are you limited by your mount in some way (star adventurer or AZGti or similar?) - if not - look at 80-100mm range of refractors with good field flattener.

I have TS 80mm F/6 APO and it is indeed very nice little scope. With Riccardi reducer you will get nice F/4.5 scope and about 360mm FL - however, for imaging of galaxies I would choose something with a bit more oomph - maybe this scope:

https://www.teleskop-express.de/shop/product_info.php/info/p11871_NEU--TS-Optics-PHOTOLINE-115-mm-f-7-Triplet-Apo---2-5--RAP-focuser.html

I linked that one on purpose (there same model without discount price) - because I believe discount price is worth having since these are supposed to be showroom models at lower price. One of member recently purchased one and impressions were good (search the SGL - there is topic about it).

Hi, do you know if TS have UK retailers, if so i'll check them out?

[vlaiv]

6 minutes ago, Spider-Man said:

Hi, do you know if TS have UK retailers, if so i'll check them out?

Have no idea. I know that Altair Astro sources scope from same supplier (only different branding, but could contain different coatings and or glass types - can't be sure). Check their offering:

https://www.altairastro.com/altair-wave-series-80mm-f6-super-ed-triplet-apo-2019-457-p.asp

and 115mm model:

https://www.altairastro.com/altair-wave-series-115-f7-ed-triplet-apo-453-p.asp

 

[johninderby]

Might want to consider this new scope from FLO. Very interesting specs. 👍🏻

https://www.firstlightoptics.com/stellamira-telescopes/stellamira-85mm-ed2-triplet-f6-6-apo-refractor-telescope.html

[Timebandit]

 

 

 

The SW ED80 is a well respected and widely used scope for AP and gets very good results from what I have seen. And great value as they do come up for sale second hand on this site at very sensible money. May well be worth considering

Hope this helps

 

 

 

[Floater]

4 hours ago, Floater said:

Just read something about a new launch of StellaMira scopes that might fit the bill! 🙂 (See FLO post.)

 

2 hours ago, johninderby said:

Might want to consider this new scope from FLO. Very interesting specs. 👍🏻

https://www.firstlightoptics.com/stellamira-telescopes/stellamira-85mm-ed2-triplet-f6-6-apo-refractor-telescope.html

I claim first!🤗

Edited January 31, 2020 by Floater

[Xsubmariner]

I have TS, Altair and WO triplets which are all very good. There is so much choice today which is daunting at first but great as none of them are bad. Enjoy the journey.

[Anne S]

I've got various Altair scopes. The main one is a Wave 102 triplet which I've had for about 10 years. I also have a Starwave 70edt to double up with the Wave and a 60edf which is used for travelling. I do use smallish ccd cameras with them, SX694 and Atik 428. 

if you're going to use a dslr with them you'll need a flattener or reducer.  You'd need to check whether they're suitable for a full frame camera. The most likely scope should be the Wave ones as they have bigger focuser and flatterner or reducer. My 102 has the earlier 3 inch focuser, the newer ones have 2 and 1/2 inch. The smaller scopes are 2 inch focusers which may give problems with a full frame camera. 

One day I'm going to try my Canon 650d with the 60mm but I need to get the flattener first.

 

[Spider-Man]

18 hours ago, happy-kat said:

Hi

Some galaxies are quite big so if you've any nice prime lenses I wouldn't rule them out.

What mount are you intending to used your gear on?

Hi,

I'm torn between getting a beefy goto EQ mount (SW EQ5 or similar) or going down the more portable tracker route (SW star adventurer, iOptron Sky Guider pro, or similar) haven't really decided, what would be your recommendation & why?

Any advice gratefully received.

[Spider-Man]

1 hour ago, Xsubmariner said:

I have TS, Altair and WO triplets which are all very good. There is so much choice today which is daunting at first but great as none of them are bad. Enjoy the journey.

Are modern APO telescopes like modern DSLRs, they're all quality products, just offering a slightly different feature set?

[Spider-Man]

Thank you all for your welcoming messages & messages of advice, it's going to be an interesting new hobby. 🤓

[Xsubmariner]

Spider-Man, you could take your analogy with modern cameras and apply some of it to the modern telescope world. Lighting the fuse, might I suggest that optically the modern (Chinese) triplets are much the same. Where I see differences is in the mechanical aspects, tube construction, baffles, and focusers. Not to forget finishes and appeal, I have a soft spot for the WO finish which some describe as beautiful.

[Spider-Man]

Xsubmariner, I agree everything thing I've seen and read suggests that the WO telescopes are amazing, good quality products and things of beauty.

[Len1257]

57 minutes ago, Spider-Man said:

Hi,

I'm torn between getting a beefy goto EQ mount (SW EQ5 or similar) or going down the more portable tracker route (SW star adventurer, iOptron Sky Guider pro, or similar) haven't really decided, what would be your recommendation & why?

Any advice gratefully received.

You need to decide based on your likely activity. Do you have a good dark sky location? Easy access to haul out a heavier mount and the physical ability to do it? Or will you spend time travelling to a dark sky site? I've just purchased a HEQ5 Pro and the size and weight came as a bit of a shock even after studying the specs etc. Not overly heavy compared to some but more than enough for me to manage. I went with a SW150PDS for my full frame DSLR on it but also have used a Canon 100-400mm lens with an AZ-GTi in Eq mode with good results.

[Spider-Man]

Hi Len1257, I live in Barnstaple North Devon, in a quiet close on the edge of town, which has reasonably dark skies at night and no streetlights.  However, Exmoor national park (A national Dark sky reserve) is literally 5 miles up the road.  There might be mileage in getting something like the SW EQM 35 Pro, which i understand is lighter than the EQ5 but can be configured as a camera tracker with greater load capacity than the Star Adventurer.  decisions decisions!

Edited February 1, 2020 by Spider-Man

[vlaiv]

From what I've read so far in this thread - I think it would be best if you started with your goals and expectations and build on that.

In the first post you said your interest is in AP of galaxies and nebulae.

With full frame sensor and small refractor there are in fact just a couple of galaxies that are good fit for that. M31 - our closest neighbor and M33. Such setup is very wide field (nothing wrong with that - as long as you know it will be).

For that reason, maybe best thing to do would be to go to:

https://astronomy.tools/calculators/field_of_view/

And check out some targets with scope of your choice and build on that.

For example - Let's take famous pair M81/M82 and see what sort of FOV can you expect if you use 70mm scope with FF/FR and your camera:

You see that small smudges in the center? Those are galaxies that you will be imaging.

Btw - these specs you should use when working with above field of view calculator - 4.88 um pixel size and 7360 x 4912 resolution with custom camera as Pentax K1 is not in database:

Ok. Once you have that covered and decide on best FOV - or Scope to match your camera - then you have further parameters for choice of your mount:

up to few kilograms of gear (that means 3-4) you can go with Star adventurer or AzGti mount in EQ mode - this is really suited for small focal length and scopes up to 70-80mm that are light - wide field imaging - but are highly mobile platforms.

Eq3 - Eq35 class mount is still good for wide field imaging and scopes up to 5Kg (maybe up to 6Kg on Eq35).

Eq5 you can push up to 8kg.

Heq5 you can use with - 10-11Kg of gear.

As you go up in "class" of mount - mobility goes down as bulk and weight of mount go up. But if you want to work with longer focal lengths and get close up images of targets - that is really requirement.

EQ6 type mount is really heavy. I've got Heq5 mount and it is manageable - I set it up every time and tear down and it is a chore, no question about it.

If you need mount in Heq5 class and have the funds - there are other lighter options available if you put high value on mobility and plan to image from remote locations. Have look at iOptron mounts like

https://www.firstlightoptics.com/ioptron-mounts/ioptron-cem40-center-balanced-equatorial-goto-mount.html

Btw - if you see mount weight limit - use about 60-70% of that as weight limit for imaging. For example Heq5 can hold something like 15kg and indeed I've mounted close to that weight on it but for smooth operation you really need to limit the weight on it to 10-11kg

Mount is the most important thing in AP.

 

[Padraic M]

FIrst off, I'd agree with the comments on the HEQ5 mount - best piece of kit I have, but I get a work-out every night carrying the parts downstairs and outside, then back again. The tripod and telescope are both fine for one trip. The mount head is very hefty and is a trip all to itself. Then the counterweights on this are very heavy! One in each hand is a challenge. But, it's a very solid mount and tracks well. I'd recommend it a lot, but just be aware that it's a luggable rather than a portable.

Secondly, make sure you understand Vlaiv's post about FOV above. I didn't, and managed to spend lots of money on a 2000mm SCT and a small-sensor dedicated astro camera. Now I can get hi-res pictures of a flea's ass on Aldebaran, but tough luck if I want to catch anything wider than that. My Canon DSLR is too old to integrate with Astrophotography Toolkit so I need to upgrade that. But, I have some nice Canon lenses, so the cheaper option for me in the short term is to use the astro cam with my 70-200mm F/4 L USM with appropriate adapters and a tripod mounting collar. This is while I save up for a new DSLR, and/or an ED refractor scope. It's a bit bizarre that I will end up using my old Newtonian reflector (with a modified Logitech webcam) as a guidescope for the piggybacked Canon lens!

Of course, you haven't mentioned autoguiding. The HEQ5 tracking is good but not perfect, so depending on the focal length of your scope and your expected exposure time, I would suggest you will need an autoguiding solution.

[Spider-Man]

4 hours ago, vlaiv said:

From what I've read so far in this thread - I think it would be best if you started with your goals and expectations and build on that.

In the first post you said your interest is in AP of galaxies and nebulae.

With full frame sensor and small refractor there are in fact just a couple of galaxies that are good fit for that. M31 - our closest neighbor and M33. Such setup is very wide field (nothing wrong with that - as long as you know it will be).

For that reason, maybe best thing to do would be to go to:

https://astronomy.tools/calculators/field_of_view/

And check out some targets with scope of your choice and build on that.

For example - Let's take famous pair M81/M82 and see what sort of FOV can you expect if you use 70mm scope with FF/FR and your camera:

You see that small smudges in the center? Those are galaxies that you will be imaging.

Btw - these specs you should use when working with above field of view calculator - 4.88 um pixel size and 7360 x 4912 resolution with custom camera as Pentax K1 is not in database:

Ok. Once you have that covered and decide on best FOV - or Scope to match your camera - then you have further parameters for choice of your mount:

up to few kilograms of gear (that means 3-4) you can go with Star adventurer or AzGti mount in EQ mode - this is really suited for small focal length and scopes up to 70-80mm that are light - wide field imaging - but are highly mobile platforms.

Eq3 - Eq35 class mount is still good for wide field imaging and scopes up to 5Kg (maybe up to 6Kg on Eq35).

Eq5 you can push up to 8kg.

Heq5 you can use with - 10-11Kg of gear.

As you go up in "class" of mount - mobility goes down as bulk and weight of mount go up. But if you want to work with longer focal lengths and get close up images of targets - that is really requirement.

EQ6 type mount is really heavy. I've got Heq5 mount and it is manageable - I set it up every time and tear down and it is a chore, no question about it.

If you need mount in Heq5 class and have the funds - there are other lighter options available if you put high value on mobility and plan to image from remote locations. Have look at iOptron mounts like

https://www.firstlightoptics.com/ioptron-mounts/ioptron-cem40-center-balanced-equatorial-goto-mount.html

Btw - if you see mount weight limit - use about 60-70% of that as weight limit for imaging. For example Heq5 can hold something like 15kg and indeed I've mounted close to that weight on it but for smooth operation you really need to limit the weight on it to 10-11kg

Mount is the most important thing in AP.

 

Valiv, thanks for the comprehensive advice I'll definitely check out the astronomy tools page to ascertain what sort of telescope size is appropriate.