GTom

Planning to replace my venerable canon 200mm tele with a small scope. The canon did fine with my modded 6D, does anyone have experience with the recent Altair 72EDF, is it full-frame compatible with a flattener, maybe even reducer? Is the focuser replaceable? Theoretically I could remove the 2.5" TS RAP focuser and the Riccardi reducer of my home scope (M90x1 thread) and put it on the small scope to avoid vignetting.

Neither, get an at least 8" Newtonian or SCT. Aperture rulz. The nice and shiny APO's are great for deep sky astrophotography, but simply lack the light gathering and resolving power.

I have that feeling too. Asked Altair, but they are NDA-bound to share specific details about the optical formula. IF identical to the TS (FPL53 + Lanthanum) then it is as good as a triplet and best-buy candidate. Unfortunately no glass or design CA-plot is available, someone has to try it with a wide-band L1 type luminosity filter.

Title says everything: one of the most affordable 150mm APO is the Altair 150EDF. I suspect (don't know for sure), the optical formula is the same as the TS Photoline 150/1200 doublet. Latter shown impressive results, even with lrgb filters opening in deep blue, below 400nm, eg.: https://www.astrobin.com/full/s9okh1/0/ I was wondering, may we expect the same, practically impeccable quality from the Altair as well?

Have you checked the c11 for visual, with an eyepiece?

Wheelbarrow

Anybody have first hand experience with the above 150/1200 doublet APO's? Most interested in the wide-band CA-issues, if one could use a deep-blue filter starting from 380nm with these, as well as an Astronomik L1 for luminosity. Additional info: my pixels are 6μm large, no need to squeeze the CA to super-tiny pixel scale...

Second hand C11 or a 14" goto Dob.

Transmission is indeed fine, no problem there. My question is the CA in the deep blue range: would be happy to see some real-life experience with doublets and triplets @L1 type filters.

I do not like the idea of wasting photons from our weather and work limited observation times, I was wondering: how the different breed of refractors cope with wavelengths near and a bit below 400nm? Planning to start my AP-season with a 105/735 CaF2 triplet piece (Chinese prototype, but good stuff, no idea about the mating glasses) that gives me completely CA-free lunar results for visual. Future plans may include the apm 152 or Altair/TS 150 doublet. So far the idea is to go with a Baader CCD RGB-set (B starts bit below 400nm) AND an Astronomik L1 for luminosity sets (380-720nm) - is it a bad idea? Do reducers increase CA? Just the photon-economy: L3 type is 260nm, L1 is 340nm wide, that is 30% in ranges where there is hardly any light pollution, sensors see very well and most stars emit a considerable amount.

Bucket list item, top notch work!

My house: far too North, far too cloudy and being remote still Bortle 4-5.

Even at that short FL it produces elongated stars/moons, LoL. I can't see myself paying £50 for such results not to mention 500...

My motorized EQ3-2, sitting on a solid steel tripod holds my 105/735 refractor+Barlow fine for planetary work. Would work well with the Mak too. The mount head is quite portable, the tripod is whole another story.

I believe it is an early Synta prototype. The guy I bought it from was in business relationship with them that time. Took it apart, absolutely no writing or marking on the cell, 105/735, lens in cell weighs 1535g. Thank you both for the good advice! In the meantime I'll look if I can get away with a 2" focuser with a short drawtube.

Forgot to specify, I thought about the telescope-side aperture. Camera-side is indeed great telescope side should be as big as possible. Still debating the Stellalyra and the TS 2": latter goes inside the drawtube, which is an advantage. Double price though.

I have to dig deeper (literally) in this: just got a response from FLO, that their stellamira 2" flattener's open aperture should be only 38mm! Body length is 51mm, that would place the "baffle" 106mm from the sensor, far too narrow in my book if correct. However, the TS has an extremely long backfocus, 111mm recommended. Its aperture is said to be 48mm. Not much better than, ~160mm from the sensor. Will try to confirm the aperture of the stellamira/check other options, as short backfocus+larger aperture is the winning deal here obviously if the quality is all right.

Many thanks!

If you have it at hand, can you tell the clear aperture? It is not shown in the specs unfortunately. Have you tried it with a larger (e.g. FF) sensor?

Anyone could provide a feedback on the Stellamira 2" flattener, https://www.firstlightoptics.com/stellamira-telescopes/stellamira-2-field-flattener-with-m48-adapter.html I need a 2" flattener for my 105mm f7 triplet, focuser replacement ATM is out of question unfortunately. I'd be interested in the above specimen: - clear aperture (not shown in the specs)? - vignetting on a larger (e.g. FF) sensor? - residual aberrations? - coating quality/any trouble with filters (I'll be using a mono camera, Moravian g3 16200)

Thank you, just realized myself and checked the "filter sizing tool" here: https://astronomy.tools/calculators/ccd_filter_size The replacement of the focuser seems to open a huuge can of worms, as it is not a standard M90 but a cemented tube adapter piece narrows down the tube to 70mm (69.8 to be exact) dovetail/grubscrew connection. So far I haven't succeeded removing the tube adapter. Might be willing to cut it off, but that's definitely a longer breadth project. Instead of a reducer, I'll look for a simple flattener, 1.0x should be easier on vignetting and albeit slowish, f7 is still OK for AP. Following the maths, front element of the flattener should offer 49mm aperture. Still narrow a bit for the extreme corners, but I can live with that. Found one candidate here, a user with a full frame camera already gave a positive feedback: https://www.firstlightoptics.com/stellamira-telescopes/stellamira-2-field-flattener-with-m48-adapter.html However, no idea what is the difference compared to this product, with an originally higher price tag (now sold @the same price):

I am looking for recommendations, if any 2" reducers could illuminate an APS-H (KAF-16200, diag: 35mm) FOV with a 105 f/7 APO without significant vignetting? Any flat samples with APS-h or larger cameras are most welcome. The scope is as far as I remember an early but very decent fluorite triplet in a carbon tube. As I do not know the designer and the seller can't be contacted after 15+years, can't go the "choose the matching reducer" path, need a more universal solution. Just repaired the 2" Crayford focuser, if possible I'd stay with it instead of shoveling out the price of a new 2.5" one including the troublesome removal of the narrow tube adapter.

Many thanks, I think it is screwed (hopefully) on the outside, will try to warm it with a hair drier this evening. crazy idea in case it doesn't want to come off: the black adapter piece with the thumbscrews has an ID of approx 72mm. Will try to get someone with a lathe and produce a 72 OD adapter to whatever the focuser needs. My current focuser is long, a shorter SC focuser could work.

The Crayford on my 105mm f7 generic APO gave up terribly and needs a proper replacement. 2" would be straightforward but I want to upgrade to a 2.5" RAP in order to accommodate larger format reducers/cover a FF sensor. Any idea how to replace the thread adapter that appears to be cemented on the tube? So far tried turning by hand, didn't budge at all. Last resort would be to cut it off and screw a new, larger adapter on.

Any first hand experience with this scope and the recommended planostar reducer?