TheSkySearchers

Hi all and happy new year,

For this year i will try to minimize my buying of gear but finalize or finish what is missing from last 2 years of purchased items, trying to have consistent gear for really long term and never looking back.

I have two TS-Optics 90mm CF triplets, i only used one the first one as i keep the second for later when i get a better mount or second mount anyway, and the one i am using/testing is showing really nice quality and i am happy, i didn't post examples around because i have some issues with my computers, but that didn't show the real quality of the scope really, so now i think i want to go far and add a third one to match those two in FOV mainly, if for quality too then a bonus, but i think it all depends on what i want to do, actually the third one can be used for certain data, so if i have say three telescopes and for example two OSC cameras and one mono then i can use one OSC for RGB and the mono for Lum and maybe Ha but i decided to use it for SII instead, so the third camera if i buy as OSC will be for dual band [Ha/OIII], now what do you recommend for that third telescope if it was you to decide?


1. 102mm f/7 achromatic or FPL-53 ED doublet (or FCD-1 triplet) + 0.6x reducer [stars will be removed] + IMX571C + dual band filter
2. Third 90mm, so it will be exactly same setup as two 90s i have, both are used with 0.8x reducers and IMX571 [M & C], here i will go with IMX571C can be used for RGB stars only
3. 110mm f/6 such as StellaMira doublet + Starizona APEX 0.65x + IMX571M + SII 3nm
4. 70mm f/5 Petzval + 294C, for stars only
5. 80mm f/4.4 6-elements + 294C, also for stars only
6. RedCat 51 or equivalent + 183 color, stars only
7. My Askar FRA400 + IMX571C stars only, or IMX571M with dual band for Ha/OIII


I can make that 90mm + 0.8x = 432mm as main FOV, or go with something little wider, i don't want to go longer, even 435mm-440mm i don't want, so it is almost the above options are what i could find, and they are almost affordable, less then $1500 or less than $1000, the soon budget will allow me to get one but without a camera, i even can use any above as individual alone such as 102mm or 110mm if necessary, but most likely i will do my best to put many many telescopes all at once for use per night rather than using only 1 or 2 per night, it never was good ending using 1 setup for me anyway, and i was testing two scopes together and i had few/minor issues i will fix later hopefully, so with another mount later i will try to use like 3-5 scopes at once if possible, i prefer to use mostly refractors of 80-120mm range, longer than that then i have my Newt/RC, smaller than that i already have two 60mm done or even Canon lenses, so i want to be at average 100mm aperture scopes more or less, i don't mind if achro or not good quality ED doublet so i can remove stars and use the ones from the CA corrected ones, that is why i want three scopes [or more] so i don't waste nights collecting data for each filter or band, i doubt i can spend many nights collecting data of each filter for one target only mostly if it is narrowbanding target or galaxies.


Thank you

I have a TS CF 90 f6 & 0.8FFR (432mm & a great scope) and I have paired it with my WO GT71 & 1.0 FF (420mm) on a tandem side by side arrangement

I will add a 533MM Pro to the 90mm for SHO and shoot colour on a 533MC Pro

Deserter wrote: ↑Fri Mar 10, 2023 7:54 am I have a TS CF 90 f6 & 0.8FFR (432mm & a great scope) and I have paired it with my WO GT71 & 1.0 FF (420mm) on a tandem side by side arrangement

I will add a 533MM Pro to the 90mm for SHO and shoot colour on a 533MC Pro

Good for you.

In my case i want to get as much close as possible, i can afford one of the two now, either the scope or the camera, not both, i already have two of each, so the third is a bit out of my reach and i want to complete first before i start imaging, all 90mm triplets F/6 are expensive already, the color camera is cheaper, i can buy that, but then i have two options, either 90mm with reducer which expensive for me any soon, or 72mm F/6 with 1.0 FF if available even as a doublet for example, but then it will be used either for dual band filter Ha/OIII or SII only, while one of the 90mm reduced triplet will be for RGB as i mentioned, RGB must be used by a well corrected scope, unless it is not a big deal really, i can go with 70mm F/5 Quadruplet which is about close expensive to 90mm triplet anyway.

You should get the NB on the 90mm and the OSC on the 70 if you go that way, you want resolution and detail on the better faster scope from what I can gather Tariq.

Deserter wrote: ↑Fri Mar 10, 2023 9:45 am You should get the NB on the 90mm and the OSC on the 70 if you go that way, you want resolution and detail on the better faster scope from what I can gather Tariq.

Yes, correct, that is true, also Lum filter with one of them.

But there is one big problem, STARS, because people wasted a lot to get the stars as round as possible and as corrected as possible, with NB the stars colors aren't good, and if it is not a triplet or Quad for example then i might not get color corrected stars, then there is the round shape stars, most likely the Quad/Petzval or Quint can do that effectively, so back focus also an issue, i don't know if the stars aren't much important here so we can do it with just 70mm or even 80mm and reduced.

To summarize it better, here is the following details:

1. One 90mm F/6 + 0.8x reducer + IMX571Color + Dual Band filter = Ha + OIII
2. Another 90mm F/6 + 0.8x reducer + IMX571Mono + SII or Lum = SII for NB and Lum for RGB signal such as galaxies and clusters
3. Third setup for RGB stars only, should be also at 432mm or close

What will be the best setup for #3 and can be affordable, i can buy third color IMX571, so then either 72mm F/6 or 90 triplet which is not possible any soon and wasting time waiting, or 102mm F/7 + 0.6x reducer for dual band for Ha and OIII so i leave the other two 90mm for SII and L and and RGB.

Stars have better SNR so you can capture at 70mm f6 OSC as pixel scale is similar so no problem then create star mask for post processing, ie reducing size etc. Important thing is colour which won't be an issue

Deserter wrote: ↑Fri Mar 10, 2023 7:07 pm Stars have better SNR so you can capture at 70mm f6 OSC as pixel scale is similar so no problem then create star mask for post processing, ie reducing size etc. Important thing is colour which won't be an issue

Ah ok, good to know, after all the two triplet are for the main signals and details, i think i have to accept going for cheaper option then, and if i will go cheaper option then no need to go with a third APS-C IMX571 camera then even if i find cheaper, i can just choose 294 color for stars, this way i will save more.

Deserter wrote: ↑Fri Mar 10, 2023 7:07 pm Ive had couple of glasses of wine so this is stream of consciousness thing

Irrelevant, keep this away from the topic