jetstream

Not exactly on topic but I've been looking for a used 30"+ piece of pyrex for a while now. And yes it will be in the f3's in the end.

Mine varies too, its just the way it is I guess. I can go 21.9 at times, avg 21.6 with 21.8 being common. At least we don't say the sky is 21.8 period!(or whatever). I find that observing down in a valley, pit or whatever can give more contrasted view by a bit- maybe the trees absorb natural skyglow or something. Of course I built my obs on a hill lol! Transparency is key- under dark transparent skies the MW is just a ragged display of light. I use this mostly now but do SQM for the fun of it at times.

No, just mono. Yes f4.7 and f4.8. Same optician, very smooth mirrors. The 24" specs out better on test stand than the 15" but the 15" is better in practise, the 24" can suffer minor intermittent astig from bouncing it across the gravel ie mirror cell stuff.

Why does my 24" give a brighter image of the Veil using an OIII than my 15". 24" f4.1/PCII for f4.7, 15" native f4.8. Using either the 21E or 20mm APM.

From Gerd Neumann's website "Since enough light must be available to make use of the OIII filter it is best to use this filter with apertures of more than 6" (150mm). Smaller instruments do not gather enough light for meaningful and satisfying astronomical work. However, please note: Many experienced Deep Sky observers, with apertures of more than 10" (250mm), prefer using the OIII filter instead of the more versatile UHC filter. Due to the high optical quality of the Astronomik OIII filter substrate you will see the same needle-sharp stars as you would from your regular telescope." This suggests to me that yes the aperture does contribute to the total amount of light- and continues right through the eyepiece. As a note these filters do work in smaller apertures.

Yes some types are harder for sure and can be fussy on mag IMHO.

Will a larger aperture scope pack more light into the exit pupil regardless of magnification?

Yes, I've played with this extensively, mags exit pupils whatever. I was told by big dob builders, owners and optician to use an ND filter on the moon. It will literally leave a blind spot for quite a while. I like binoviewers in these big scopes as the beamsplitter halves the light, to each eye.

Does this equate to a dimmer image of the moon using a mask at the same exit pupil? My 24" is blinding on the moon, the 15" is tolerable.

According to Simbad NGC514 has a V mag of 11.6.

should've seen me out the first time with the DSC... oh well I'm better at it now. I had a skipping, intermittent encoder too, in the cold- it turned out to be a star washer installed the wrong way. I did pour a concrete base for my scopes- just for ease of set up. I find its all a process thats for sure. What grabbed me about your report was the tight stars and the contrast seen, a very good sign.👍

Excellent. My DSC is not fussy on being level but the scope base itself must not move when using it. If it does it goes off target. 2 star alignment is vg and when I use the "realign on object" its extremely accurate. Just giving some ideas about DSC in general.

Thanks Jeremy,going to give it a try.

Wishing you guys clear skies Calvin! Eagerly waiting reports!

Now that is one awesome looking telescope. Yes the DSC are a very nice thing to have, my truss dobs also have them - what system do you have? Congrats Steve!

Yes, I saw that. I was wondering if you could run the calc. I use Bartels program for newts I play with but I don't think it will work with these. So does the secondary obstruction render this a 7.3" scope? what is the true obstructions effect on true focal ratio?

@vlaiv, what is the fully illuminated field of this telescope? maybe need to assume a low power widefield ep?

Thanks Vlaiv. Right now I switched my 75mm from the 200mm f3.8 for the 63mm from the VX10 with both running around 30% now. The VX10 is still giving VG lunar views and the illumination of the 200mm is acceptable. Anyway, a good refractor in the 100-120mm range will offer good viewing opportunities eventhough detail will suffer from the C8. A good C8 is no slouch however if it is cooled and collimated.

scratch this I just saw its 34% obstructed.

Vlaiv did you see that it has only 29% obstruction? The f12 must help it out on this. These scopes look good. IME every bit under 30% CO makes a nice difference.

Totally agree.

In my wanderings through the sky I've noticed that if the Milky Way isn't prominent all DSO, espc M33 and M101 are more difficult. In dark skies with your 28mm EP it will be bright with your scope. One thing that might show it to you is a higher power, wider TFOV EP- does your scope take 2" EPs?

Yes, our Heritage 130 and 24mm ES 68 gives this. The view of M33 is bright, no structure in this scope here.

What did the Milky Way look like when you tried to observe it?

Hey John, I only have the 2" Baader/Zeiss prism diagonal but in the TSA120 I detect no scatter with it. I checked straight through as well, no discernible difference to my eyes. I used the very low scatter Zeiss zoom and Vixen Hr's to check.