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Messages - satimoja

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As you hsve read in earlier posts doubles can be gravitationally linked or visual by being nearby. I enjoy them a lot because you can see most even from light polluted skies and seeing does not have to be perfect for most except the very tightest. Once you start viewing them you will get hooked. I especially enjoy some of the more colored pairs. Make a list and start hunting.

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Beginners Forum / Re: In need of assistance, thanks in advance!
« on: February 09, 2018, 04:33:38 AM »
Lee14 is right. You would not buy a car without test driving it. Same applies to a significant investment like a telescope. Most astronomy clubs will have members who own a wide range of scopes. Attending one or two observing sessions would give you a good feel for what meets your needs best, and you might even find some members with good equipment for sale at significant savings.

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I just realized if a spherical primary mirror and a spherical achromat both are done correctly, the achromat will have 1/10th the spherical aberration, since both surfaces can share the curvature. Actually it might be 20:1. I looked at a report of calculate spherical aberration on lens that were symetrical, plano convex, and optimized. The optimized one had 1/10th the aberration of the worst. Optimized was a more convex surfaces facing front, and a slightly convex surfacing facing back. I don't recall if the worst surface looked at was the symmetrical one, or if they went as far as to do a plano front and convex back, which would be the equivalent of a spherical mirror.
Spherical aberration also gets worse with increasing diameter and decreasing f#.

The Skymaster is f4.6 vs 3.9 of the Firstscope, at it is 70mm vs 76mm. The objective is probably closer to optimized, whereas the Firstscope objective is necessarily in the worst configuration for spherical aberration. The skymaster would have a little less field curvature, and less astigmatism of the eyepeice. Maybe I could use a mirror to fold it and put the eyepiece where I want.

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Beginners Forum / Re: Packing up your gear
« on: February 03, 2018, 05:12:43 AM »
I use the original Meade LX200 box and foam to take my scope everywhere. I tighten the cover down with a thick strap-belt that holds everything firmly in place. I have even shipped it on an airplane that way. Meade sends the scopes around the world in that packaging so it has to be pretty good (knock on wood ).

When shipping or transporting the scope by car, one should leave the RA and DEC locking knobs loose. That way the scope has some freedom to bobble around in the packaging box a bit without tearing up the long-term holding strength of those locking knobs.

For the airplane trip, I was also advised to turn the scope's manual focusing knob all the way back to its loosest position. That parked the primary mirror way in the back of the scope where it would be more secure and have less play to jiggle around.

Mike

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I just sold a couple Pentax XW's after I thought my much less expensive GSO Superviews were putting up the same or better views on the moon and Jupiter in my 2 refractors, one f/9 and one f/9.2. It could be my 55yo eyes that just can't see the difference but is there any benefit to using an eyepiece like the XW's or the Delos or Ethos eyepieces with a longer focal length refractor?


I'm kind of looking at this the other way round.

The out of focus edges in the 14 and 20mm XWs becomes quite tolerable at a focal length of 1200mm (in my case a 152mm). Not so much your 4" with its relatively short focal length.

In that case I'd prefer Delos or Ethos to XW, and also--I strongly suspect--to the GSOs, though I have not tried those.

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Jim, get the ES 12mm 92 degree. I am loving it. Also the 17mm! They are huge and very heavy, however. But even in my Tak FC-100DL they work great.

Is there an advantage over the 100-degree units? I think part of the "problem" with herr Docteris that it is an eyepiece designed for daytime long distance binocular use and that the eye relief that is beneficial for its primary use case is actually detrimental to the "immersiveness" when used as an astronomical UWA. I don't wear glasses when I observe, but do appreciate LER at high magnifications. But not alway at low magnification.

That said, it is pretty ingenious of JOC to be able to combine 10-degrees more AFOV than a Naglerinto a LER design. They've really come a long way since being a cloner earlier in their history. I love it.

Regards,

Jim

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Reflectors Telescopes Forum / Re: Bomber Bob Going DOB?
« on: February 02, 2018, 07:00:26 PM »
It's a 4 year old Orion XT12g, 12" f/5 Newtonian (FL 1500mm), with a total weight of 102 lbs... Yikes!! Besides the standard stuff, it has a full-aperture mylar solar filter. It's been sitting idle for a couple of years and getting dusty, but I don't I mind a bit of elbow grease. The primary mirror has a centered collimation donut. The weather kept me from star-testing it, but daylight viewing is impressive.

We tried to be careful loading it in the back of my VW Touareg, but managed to put a dent in the tube anyway. (I'll take that out with my rubber mallet later.) Now that I know the best way to position it, that won't happen again. Since it breaks down into two 50# chunks, it's really not that bad loading & unloading - except for our 104F heat index today!

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I still see that i'm a beginner as I learn something new every day
Welcome to the rest of your life.

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aorion314 here, after prompting from my CN peers and about 2 hours of internet research it is clear that the Polemaster is the best product and clearly money well spent

I was pricing the Polar Scope last night: $240 from Losmandy in CA, but nearly €400 from teleskop-express.de. I shall investigate the Polemaster alternative, which is €390 from the same place, with adaptor.

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I was told that they are still squishing a few bugs in the new version of APCC and it will be released as soon as that is done.

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One of the most important things I try to focus on while working with the public is making sure they everyone possible comes away from their visit with a very positive feeling about astronomy and especially their astronomy experience on Mauna Kea. I never challenge anyone's political, religious or global warming beliefs. However I will diplomatically defend astronomy and general scientific research when I have to. I often point out that in the USA, more is spent on social welfare programs in one day than what NASA gets for a budget for an entire year. Easily verified by visiting the government ONB web site for the U.S. annual budget.

The stress of the TMT conflict has made diplomacy and kindness especially hard for many VIS staff to maintain.

I hope to work with the new VIS manager and new VIS volunteer coordinator on new orientation and training materials for staff and volunteers that better-focuses on that positive experience for visitors.

If there are any videographers out there who would be willing to contribute a little time to some new outreach training videos, that would be awesome. I also need updated basic training videos for using and operating Astro-Physics, Meade LX200, Celestron CGE-Pro and non-GOTO Losmandy G-11 mounts.

The small herd of Orion dobs break down under rough handling so frequently that they don't get brought out on the deck as often as they used to. Mostly focuser and finder failures.

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Beginners Forum / Re: Stargazing on cold nights
« on: January 31, 2018, 01:06:37 AM »
Along with the clothing tips a hand warmer is essential IMO. Not only for your hands but to warm a hand controller up. I'm going to try an electronic one this year.
You can get these for ~$25.

https://www.amazon.c...r/dp/B00HMA9O5S

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Surplus Shed has some un-cemented doublets. Would one of those work in the variable spacing arrangements?

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Reflectors Telescopes Forum / Re: Infernal Blue Film on Mirror
« on: January 26, 2018, 08:35:36 AM »
It worked. Evidentially whatever they add to the other colors is oily. But the original stuff cleans it well.

Thanks everyone.

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Eyepieces Questions & Recommendations / Re: Meade HD-60 18mm
« on: January 26, 2018, 12:22:16 AM »
You probably should have said that to start with. - It would have saved us both some time.Thanks,

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