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Re: 90mm Mak

Posted: Sat Mar 14, 2020 10:59 am
by pakarinen
First light - clouds were rolling in, but I was able to spend a little time on Polarus, Sirius, and M41.
Time was limited, so I just mounted it on my Benro tripod and went out the door.

Collimation looks pretty good to me - nice concentric rings. I have astigmatism and my prescription is close to two years old, so even with glasses, I might be off a bit.

M41 looked good, but with that high f-ratio, the FOV clamps down pretty quickly. I didn’t go shorter than 10mm.

Supposed to be clear tomorrow morning, so I’m hoping to get some moon viewing in and maybe Saturn as well as trying it on my TW 1.

Re: 90mm Mak

Posted: Mon Mar 16, 2020 5:53 am
by Bigzmey
Congrats on the first light Pakarinen! Is that F13.8 Mak? You will find that in comparison to the F5 refractors the EP range is shifted towards longer FL. On a typical night it will be between 14mm and 40mm EPs.

Re: 90mm Mak

Posted: Mon Mar 16, 2020 12:00 pm
by pakarinen
Yes, it's the 13.8. I took it down to 10mm (VIxen SLV) briefly this morning on the moon although there was some high cloud. Not super sharp b/c of the clouds, but looks promising. Also showed me how dirty my diagonal is...

Re: 90mm Mak

Posted: Wed Mar 25, 2020 9:26 pm
by pakarinen
Had a brief session this morning.

Albireo - looked good, sharp, nice colors
Ring - Just meh, but from home the Ring is usually not much better than "meh", so it's probably not a fair test.
Epsilon Lyr - this was the highlight. I was able to fleetingly resolve Eps 2 at 208X. Problem was that the FOV is so small at that magnification that Eps was flying through the FOV so I spent most of my time tracking it.

Maybe some moon time soon.

Re: 90mm Mak

Posted: Thu Mar 26, 2020 12:03 am
by Bigzmey
Nice that you manage more observing Pakarinen. Yes, tracking at high powers can get tricky. What mount do you use?

Re: 90mm Mak

Posted: Thu Mar 26, 2020 1:07 pm
by pakarinen
Twilight 1 (with slo-mo). I really like the specs of some of the other alt-az mounts, but I'm reluctant to give up slo-mo.

I've considered getting an M1V just to see how well I can do without slo-mo but I haven't felt like spending the money.

Re: 90mm Mak

Posted: Thu Mar 26, 2020 6:50 pm
by Bigzmey
pakarinen wrote: Thu Mar 26, 2020 1:07 pm Twilight 1 (with slo-mo). I really like the specs of some of the other alt-az mounts, but I'm reluctant to give up slo-mo.

I've considered getting an M1V just to see how well I can do without slo-mo but I haven't felt like spending the money.
Slow motion is critical for the scopes with narrow FOV. I tried a couple of AltAz manual mounts without slo-mo, and it becomes painful to truck at high powers.