Did someone say 8 inches? - Askar 203mm apo triplet

[globular]

15 minutes ago, Louis D said:

It's not just about the glass and optical figure/correction.  It's also about the entire mechanical construction as well.

I imagine the cell for the 203 will be of similar construction to the rest of the Askar APO range.
Yes those are smaller, but this isn't really (only) a size issue - as you know with your 90mm.

Have there been widespread concerns with pinching on the Askar APOs? There should be enough of them in the field now to know if this a real concern or not.

[Genuine question as I'm not that well read on them.]

[Elp]

1 hour ago, Louis D said:

Exactly.  From what I've read online, APs are the same way.  That's my point.  It's not just about the glass and optical figure/correction.  It's also about the entire mechanical construction as well.

You can't compare the cooldown time between a doublet and a triplet, two different things, for imaging add in a flattener and there's even more glass. I think they're designed more for imaging as most triplets are, even though some of the apo range are binoviewer friendly.

The focusers are supposed to be good from what I've read.

Edited August 9 by Elp

[Elp]

22 minutes ago, globular said:

Have there been widespread concerns with pinching on the Askar APOs? There should be enough of them in the field now to know if this a real concern or not.

[Genuine question as I'm not that well read on them.]

I've probably seen feedback from around 8 people at least, only the one had an issue and it was quickly rectified by adding a dew heater further behind the front lens.

Others have issues with Askars spot diagrams as they say the specs are bloated to begin with, and that they've sacrificed centre sharpness (which I believe are where they're measured) to achieve a more even sharpness throughout the lens area to edge.

Nico Carver (Nebula Photos on YT) tested the 103 against four other 4 inchers (more expensive bear in mind) and the imaging performance was generally good up until the 0.6x reducer. Don't know if it scales the larger aperture you go. And before anyone comments on sponsored YT'er, most other channels have also found the performance good. I think Sarah Matthews had pinched optics too.

Edited August 9 by Elp

[Elp]

On 09/08/2024 at 18:27, Steve Ward said:

I know one thing , I wouldn't trust this little mount to carry it however clever they might be ... 😂

 

Not quite the same level but here's a SW Wave150 (see around 32-35 mins) with a C11 and 180mm refractor (though the latter is with CW and beefy steel tripod):

 

[CraigT82]

That’s interesting that at about 33.30 he mentions that these “are low mass mounts so breezes and stuff….” will make it wobble presumably. Also the saddle on this particular mount looks very small for bigger scopes, putting a lot of trust in it by mounting that big frac. 

[900SL]

I don't see the point in this. You'll need a permanent set up, it requires a serious mount, the price rules out high end glass or figure, and a reflector at 1/5 of the price will out perform it. Fool and his money..

[Elp]

2 hours ago, 900SL said:

a reflector at 1/5 of the price will out perform it

True, but some people just prefer refractors.

[DirkSteele]

As someone who has a 180mm LZOS triplet, and only did not buy the 8” because I wanted to take it star parties, I do struggle to understand the key selling point.

Such a scope requires a permanent home and a heck of a mount. Combined with those extra costs, it is hard to see the value over a mirror based scope. Especially, if there are some compromises around the optical quality.

Edited August 21 by DirkSteele
Typo

[DaveS]

Well, I have an obsy, and my DDM 85 is well up to the job of caring it but would I gain anything over my ODK 12? I have my doubts.

[Mr Spock]

I do like refractors. However, if I was in the position of having a permanent observatory, I would (as a planetary observer) most likely fit it with a C14.

Alternatively dismount my 12" Dob and fit it with rings. It would have to be alt-az tracking though due to fiddly eye position. You can rotate the tube with an extra ring, but 12" is a lump to move like that. No refractor, large or small, has come close to the lunar detail I can see with the 12". What it's like to view the moon's surface razor sharp at x461 cannot be described.

[dweller25]

Refractors are my favourite scope but my back complains above 5”, so then I move to reflectors.