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Topics - coreanoguf

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I want to preface this - I now have the gamut of scopes - a 8 inch Celestron C8 classic Orange tube , a 10 inch orion Dobson , a Meade 90 MM refractor goto , and last but not least a 4.5 reflector on a nice german eq mount - I read about people who have zambuto mirrors that have certain strehl ratios and ooh and ahhh about being able to go to 300x magnification-my question to you with more experience - I cant seem to go above 120X or 150X in magnification without things going soft. Chasing perfect scope I can do - but in the end where or what do I fix - my eyes are 55 years old - I don't see very good - I don't think I can improve my C8, on the refractor I cant improve it - but the things I can change is the 10 inch orion Dobson - it is factory made - is it worth getting the 10 inch mirror refigured , would it improve my lot in life ? What about the secondary - how important or quantam leap is a secondary with 99% reflectivity and made from quartz will improve my lot in life?
Is a 500 dollar eyepiece going to significantly improve my views ? Inquiring minds want to know...

I just gave myself a one-year astronomy fix by putting down deposits for a JP Astrocraft "Sweet 16" scope as well as a Lockwood 1.1-thick Cer-Vit mirror. The speed will probably be about f/3.7 to allow a very comfortable seated position even at zenith, where the eyepiece will be at ~60". The scope and mirror probably won't be ready until next summer at the earliest, but that does give me time to nail down the details.

I've got two kinda stupid questions, "stupid" in the sense that despite doing research I still haven't come to a concrete conclusion!

1. In terms of determining whether I should put the focuser on the left or right side of the scope (when viewed from the back), this second half on body temperature in this Daniel Mounsey article (as well as his numerous other CN posts) has been very helpful.

I live and observe in Boston. Is there a prevalent (marine layer) nighttime wind direction in Boston? Logan airport seems to report that the wind is NW-ish most of the year but day-to-day I seem to observe a more expected wind from the east at night. For some strange reason, despite being left-eyed, I greatly prefer having the focuser on the left side which would be work well with a wind from the W to NW.

2. I have precious little time to observe nowadays. We're talking less than half an hour, with a hoped-for setup time less than 5 minutes -- including wheeling the scope in and out. I also don't have the bandwidth to set up a scope beforehand: with a growing family I will inevitably forget that I had set up the scope and it will rain overnight and the sun will burn my house down the next day! So not only is cooldown important but high quality views *while* the scope cools down is of utmost importance.

The thin Cer-Vit mirror should hold its figure and cool down rapidly. That leaves the boundary layer to deal with in those precious first few minutes: what’s the latest thought on removing its effect?

FYI: this wondrous thread has been my guide on boundary layer mitigation, but it is from 2005. Daniel Mounsey concluded at the time that it is sufficient to have a single rear fan blowing on the primary as well as a bank of venting fans on the top side of the mirror box to pull the boundary layer off, kitchen hood-style.

At the same time, Mike Lockwood just posted an interesting article on a customer's method of merely "stirring" the boundary layer with four internal fans with zero venting to the outside other than what goes out the top of the scope.

Perhaps the best combination would be a couple "stirring" fans at the bottom of the mirror box, pointed directly at the mirror at very low speed to assist in stirring the boundary layer (mitigating its effect while it exists), plus a bank of fans Daniel Mounsey-style at the top of the box to pull out the (now-stirred) boundary layer? Or is the bank of pull fans sufficient (or even better) by themselves?

Mounts Questions & Expirience / IEQ45 Pro or EQ6-R, which would you choose?
« on: December 28, 2017, 03:51:55 AM »
Should be getting enough money right off to buy either one. Between the two which would you choose? I may attempt the SN10 on whichever one, but would mainly use it for the 8RC. One of the things I do is lots of unguided, so I will still do so with these because my poor laptop needs a bit of TLC. Prime focus DSLR work is what I generally do.

Light Pollution Topics / Bortle scale accuracy?
« on: December 28, 2017, 01:32:40 AM »
I don't normally come over to this forum but i am hoping to clear something up.  I was told once that the clear sky clock Bortle scale has had some areas assigned their respective colors based on info taken when snow was on the ground and is therefore inaccurate.  These areas would be asigned colors that suggest the sites are not as good as they should be.  My primary summer site in lower Michigan is a yellow zone but it seems more like a green zone to me...

Beginners Forum / Finally First Light...WoW!...few questions.
« on: December 27, 2017, 12:42:47 PM »
After getting my new Bresser AR127L 1200mm F9 refractor over 3 weeks ago..finally a clear last week to get an hour at a dark site bouncing around with my new AVX ,with incl. cheap eyepieces, had a wonderful time looking at clusters,and a few DSOs ,the mount I got down,and works flawlessly.. After receiving my new HD60 6pc set and a ES 18mm 2" eyepiece, got up this morning at 4 am got the scope out with a quick align to view Jupiter,just in my yard, with low to moderate light pollution. AND WOW!!!! Started out with a 12mm and immediately saw cloud bands,and 5 moons..I popped in a 6.5mm and it just blew me away.Tried a 4.5mm ,but more detail was shown with the 6. To much mag I guess.only questions or problems was this:
The focuser on this this is very course, single speed R&P, after a lot of research, I've read in multiple posts that this one has a lens in the focuser itself, leading me to believe I can't upgrade it to a two speed.I haven't took it apart to actually see if there's a lens, not sure if I know how and the scope was just collimated ,this scope is almost identical to the old Meade AR5...Minus the lens...I think. Can I somehow change just part of it, or am I doomed to keep it and deal with the tough job of focusing.
Also ,I know that some simple filters will increase the detail dramatically, as the planet was somewhat whitewashed ,can I use the imaging filters for visual? Reason being...I may get a simple CCD or something in a kit to take pics and stack them,and why buy two sets if I don't need to.right now I'm sticking with visual,learning more sky.But eventually wanna take simple pics to show off my new hobby.

ATM, Optics and DIY Forum / Building a Foucault tester.
« on: December 25, 2017, 02:22:15 PM »
I will facilitate my was into ATMing and thought I'd construct a Foucault tester.

The principle of the Foucault and the Ronchi I more or less grip, but I had some interest in attaching a camera to it.  Can somebody clarify the features of a lens/camera combo that would work well for all these testers?  Some I see use a DSLR, some use a webcam, some appear to utilize just a tiny telescope that they made.  Quite frequently I see it stated to post a picture of the evaluation to accompany questions, so I would incorporate it from the start.

This will be a good opportunity to utilize some various aluminum extrusions and random hardware I have been saving through time.  Although I am not adverse to using some timber parts too when it comes down to it.
In this pile are various kinds of digital measuring apparatus, hopefully one of them will be appropriate.
I'd like to construct a Foucault/Ronchi combo very similar to this video that Pinbout posted of the "Swayze" kind tester.

Any other hints would be appreciated also.

Oh, one more thing, are Teflon surfaces absolutely vital?  I am not against it, just I would have to get a thing and was wondering if these furniture feet items would be sufficient for the sliding surfaces.

Light Pollution Topics / Christmas decorations
« on: December 24, 2017, 03:13:07 AM »
Need I say more....   Especially the blue flashing ones out of the neighbors give interesting effects.F.

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