small refractor recommendations for a ioptron star tracker pro

[Your Star Will Shine]

I love my recently purchased ioptron tracking mount and want to go a bit further than widefield with my DSLR.

The max payload with the counter balance (which I have) is 3kg so using my Nikon what would be a good refractor to team up with this set up.

I have a tight budget of £200 to £500 on the secondhand market.

Many thanks in advance 

[callisto]

2 hours ago, Your Star Will Shine said:

I love my recently purchased ioptron tracking mount and want to go a bit further than widefield with my DSLR.

The max payload with the counter balance (which I have) is 3kg so using my Nikon what would be a good refractor to team up with this set up.

I have a tight budget of £200 to £500 on the secondhand market.

Many thanks in advance 

I think it will be a bit tight on the payload with a small scope...I had the SGP married with a Zenithstar 61 II and with camera/focuser etc was not far touching the limit on that 🤨

Maybe something like a WO Redcat...only 1.5kg?

Edited November 8, 2021 by callisto
change wording

[Your Star Will Shine]

On 08/11/2021 at 20:30, callisto said:

I think it will be a bit tight on the payload with a small scope...I had the SGP married with a Zenithstar 61 II and with camera/focuser etc was not far touching the limit on that 🤨

Maybe something like a WO Redcat...only 1.5kg?

yeah its a tricky one I stumbled across a good article on the subject which helped........ these are my choices:

WO Z61

Altair 60EDF

SW Evostar 72ED

Redcat

[callisto]

2 minutes ago, Your Star Will Shine said:

yeah its a tricky one I stumbled across a good article on the subject which helped........ these are my choices:

WO Z61

Altair 60EDF

SW Evostar 72ED

Redcat

Yeah, you need to keep the load weight down as much as you can...keep an eye out for a used Redcat, although it would be at the top of you budget 

[raadoo]

As @callisto said, weight is your primary concern, so as light as possible is the way to go. On top of that you're also quite constrained by your budget, but I think you have a few more options aside from the RedCat:

 

Nikon 180mm f/2.8 ED AF-D

— found one used at Ffordes for £379

Assuming 180mm is tighter that what you're shooting now, this one is widely regarded as one of the best Nikon lenses for infinity focus, coma correction and sharpness, even at f/2.8. And at a mere 800g it's not going to cause your tracker to break into sweats. I had one and used it a few times with my D610. It's an excellent performer and that f/2.8 really helps with getting a lot of detail out of short exposures.

 

 

Nikon 300mm f/4 D IF-ED

— found one used at mpb for £519

If you want to get in tighter and really give small 60mm refractors a run for their money, then this is the one. Yes, there's an f/2.8 version of this but that one is a) over your budget and b) much too heavy for a tracker. The f/4 fits your budget, weighs in at 1400g at will perform well at f/4 and excellent at f/5.6. I had an older version of this (non D) which was very good and the D version here is supposedly even better in terms of sharpness and aberration correction.

 

Askar FMA230 ED

— can be had new from FLO for £589

It's a real refractor. It's got a reducer that can get you to a field corrected 230mm f/4.6. It weighs in at just shy over 1kg. It's made by Sharpstar. And while I haven't used it specifically, I am beyond thrilled with how its bigger cousin, the FRA400, performs, so that should tell you that Askar/Sharpstar know what they're doing (which is no secret, really). In case you didn't know, Askar is the sort of photo lens technology applied to astronomy division of Sharpstar and any of the Askar lenses is quite well suited to take a DSLR / MILC at the back end.

 

Worth keeping in mind that depending on the model, your camera may be able to autofocus the Nikons above, which would render them quite useful for daytime photography.

 

 

[900SL]

2 hours ago, raadoo said:

As @callisto said, weight is your primary concern, so as light as possible is the way to go. On top of that you're also quite constrained by your budget, but I think you have a few more options aside from the RedCat:

 

Nikon 180mm f/2.8 ED AF-D

— found one used at Ffordes for £379

Assuming 180mm is tighter that what you're shooting now, this one is widely regarded as one of the best Nikon lenses for infinity focus, coma correction and sharpness, even at f/2.8. And at a mere 800g it's not going to cause your tracker to break into sweats. I had one and used it a few times with my D610. It's an excellent performer and that f/2.8 really helps with getting a lot of detail out of short exposures.

 

 

Nikon 300mm f/4 D IF-ED

— found one used at mpb for £519

If you want to get in tighter and really give small 60mm refractors a run for their money, then this is the one. Yes, there's an f/2.8 version of this but that one is a) over your budget and b) much too heavy for a tracker. The f/4 fits your budget, weighs in at 1400g at will perform well at f/4 and excellent at f/5.6. I had an older version of this (non D) which was very good and the D version here is supposedly even better in terms of sharpness and aberration correction.

 

Askar FMA230 ED

— can be had new from FLO for £589

It's a real refractor. It's got a reducer that can get you to a field corrected 230mm f/4.6. It weighs in at just shy over 1kg. It's made by Sharpstar. And while I haven't used it specifically, I am beyond thrilled with how its bigger cousin, the FRA400, performs, so that should tell you that Askar/Sharpstar know what they're doing (which is no secret, really). In case you didn't know, Askar is the sort of photo lens technology applied to astronomy division of Sharpstar and any of the Askar lenses is quite well suited to take a DSLR / MILC at the back end.

 

Worth keeping in mind that depending on the model, your camera may be able to autofocus the Nikons above, which would render them quite useful for daytime photography.

 

 

I get a lot of chromatic aberration (blue bloat) with the Askar 180.  I'd like to see a full review of the FMA230.

The Nikon 180 (ED glass) is a great sharp lens provided you get a good copy. Some can have coma if out of whack/ sample variation.

[callisto]

3 hours ago, raadoo said:

I think you have a few more options aside from the RedCat:

Yeah, very true 

I used to have the Askar ACL 200mm f/4 lens...tack sharp but a heavy lump at 1.8kg and way over budget 🙄

[woldsman]

Your payload of 3Kg is a limiting factor. In this budget range, there will be some chromatic aberration but I would not stress about this as you have to pay way more to avoid it. The Askar range looks enticing although you don’t say what your current setup is. As well as the FMA230, you can consider the cheaper FMA180 (available below £300?) or the ACL200 mm f4 which is £692 new from FLO. These  should all retain a big proportion of their value if you look after them and decide to sell them later on. There is also sharpstar’s 61EDPH II although you will need a reducer. You can attach a filter wheel to this if you upgrade the DSLR to a CCD. I think the weight limit is under 3Kg still. But going back to your weight and payload limits, if you want to stick to these I think I would opt for the FMA180 as the tracker you are using should reward you with good exposure - it’s less than 400g!

[Alien 13]

No one has mentioned the Samyang 135mm f/2 yet, an ideal match for a DSLR and "star tracker".

Alan