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Messages - adviconno

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General Astronomy & Observing / Re: How many people have observed ___ ?
« on: February 09, 2018, 05:51:17 AM »

<p class="citation">QuoteThe Messier and Herschel awards give solid evidence of how many people have seen all of the objects on those lists. Beyond that, we can't really assume that very many others have seen all of them, though a small number could very well have, or at least a large percentage of the objects in the lists, more for the Messiers, fewer for the Herschels. Or maybe not.

I have seen all the Messier objects but I have made no attempt to view objects on the Herschel lists because my interests and style take me elsewhere. I suspect many are like me, in this day and age, the access to large databases makes doing it your own way quite easy.


Similarfor me. I did all of the Messier's the first year I had a scope, all of the planets, all of the moons visible in that scope and would target NGC's shown in Sky Atlas 2000. I printed Herschel 400 and 2500lists and logged some, but mostly I quit logging the less interesting ones and I did not pursue these lists systematically. I have restarted logging them, but I still oftenneglect to go back and crosscheck. Once the list reaches much above a hundred, completion of it becomes challenging. Part of that is remembering to pull out the list throughout the year to fill gaps.

I tend to work a "project" area,sometimes from articles, sometimes just a page in Uranometria, sometimesDSO'ssurrounding a galaxy that has a supernova. Probably less than half of what I observe gets recorded even when I am making an effort to doso and maybe half of that doesn't make it on my Herschel lists. I spend more time chasing "squirrels" I notice along the way--15th magnitude galaxies thataren't on my charts. When I findsomething brighter andinteresting and am not sure if I have observed it in the past, I mostoften find old notes for itfrom the early days with the SCT.

While the certificates are one way to make an estimate, it is going to be difficult to come up with a multiple for those who did the lists (or most of a given list) withoutpursuing a certificate. Record keepingis an issue with the longer lists and I doubt most log frequently enough (reminding myself that I need to trudge through abacklog of several hundred galaxies observed recentlybut not yet checked against the Herschel lists.)
There might be other ways to make estimates.

Maybe 50,000 objects are visible in a 20-inch telescope?

Maybe 100 observers are inclined to go after some of the 49,000 of those that we presume most people won't look for?

They could each have 490 objects of their own.

A thousand such observers could each have 49 objects of their own, but nothing really stops them from eventually observing 490 if they choose, except maybe a shortage of 20-inch telescopes?

Actually kinda hard to miss Forum list.jpg

I see that in my aging years, I'm beginning to suffer from fine print myopia. 

I want to thank you ALL for helping me find things - lastly Dave and Greg. It's truly one of the best forums and informational websites on the internet - always thought so, but just could not find things today. You guys are doing an EXCELLENT JOB - really!

Reflectors Telescopes Forum / Re: Will all Small Reflectors be Toys?
« on: February 04, 2018, 01:43:52 PM »
I think that newt is a nice basis to build an atm newt from it.
A longer tube made from good material, internally flocked,
smaller secondary, that focusser without an extension,
that would make a good small newt.

Of the various 130 mm F/5s I have owned, the first Space Probe 130ST had the best optics and it was fitted with a 2 inch focuser.

It did a good job for what it was but I always had it in the back of my mind to rebuild it much as you suggest. A longer OTA, aluminum or maybe phenolic and well flocked, a low profile, high quality two speed, a smaller secondary..

Also, these scopes cool rather slowly even after removing the rear cell cover. Getting 300x to split near Dawes limit doubles takes most of an hour. A proper mirror cell along the lines of the RV-6 was what I was thinking, minimal blockage, a nice free air path.

Regarding the Parks scopes: when we moved our current home, in 1999,Scope City was just a few blocks away. Their Newtonians, large and small were probably very good for the 1980s technology but they didn't seem to have embraced the changes that were happening. I remember going in the store and asking for a laser collimator.."We don't believe inlaser collimators.". I don't think they believed in two speed focuser, thinner mirrors etc.

So, the scope I am imagining is a 5 inch, maybe a 6 inch, built to high standards. A scope where design decisions are not made on the basis of cost but rather based on making the best scope possible..

But I think in the final analysis, Don is likely correct, such a scope would not sell and small high quality Newtonians are ATM projects.


Like I've said before...never look through an eyepiece you can't can never go back

Reflectors Telescopes Forum / Re: Large mirror cleaning
« on: February 02, 2018, 05:13:18 PM »
I do use the OWL method which Gary Seronik also recommends. However after 10 years my 14 needed a re coat as I live fairly close to salt water. I believe it cost about $100 plus shipping and it included re coating the secondary. I cleaned mine last summer and it still is pretty clean. Previously I did use surgical cotton but I believe the OWL is better. I haven't had any problem with scratches.

Jon, thanks for sharing a little history on how you got started in astronomy. Not the same as my experience, but very interesting just the same. Although you think it's important to recognize you can enjoy astronomy with inferior eyepieces, that's not very important to me at all. I never have the time I want to observe, so when I'm out there, I want the best views I can get. That why I encourage people to get the best they can, so they will enjoy this hobby more. The OP might not like my advice, that's OK, but many people read these posts &amp; some might like my advice &amp; save for better gear. So my post is for someone in a similar situation who wants to get it right the first time &amp; not squander money on something they won't enjoy.

I do have some wonderful equipment and I enjoy observing with it.

When it comes to the wide field viewing, there is really nothing that is as perfect as the NP-101 combined with the 41mm Pan, the 35mm Pan and the 31mm Nagler. As I like to say, that's as close to heaven as I will ever get. Spend some time with that scope and those eyepieces and the field curvature in other short focal length refractors, the astigmatism in other eyepieces, they can be quite apparent.

So, in retrospect, knowing that there are more perfect scopes out there than what you might have, do you think you should have waited until you could buy the most perfect scope or was it wiser to go ahead with some nice scopes that provide good views?

Myself, when someone asks about eyepieces under $150, I try to figure out the best solution for them based on my experience, I can enjoy the views through the AR-102 with an ES-35 70 degree.. To me, time spent waiting is time lost observing, learning.

One advantage to starting out with affordable eyepieces is that one learns about eyepieces and what one likes. When it does come time, if ever, for the high end eyepieces, you know why you have chosen that particular eyepiece.



Come visit the International Occultation Timing Association (IOTA) booth at NEAF and learn how to do real research with equipment you already own. Classes offered on Saturday and Sunday on getting started timing occultations. Measure the sizes and shapes of asteroids to km resolution, discover double stars, help the Kepler2 mission, co-author scientific papers... the list goes on and on. Hope to see you there!

&gt;&gt;&gt;&gt;&gt;&gt;I'm going to do the quiet unexciting thing of watching the bite out of the pinhole shadows of the leaves, as it progresses, and then diminishes. It sounds like way too much of a production to try for being in the path of the totality; and I did get to do that once before in my life.&gt;&gt;&gt;&gt;&gt;The 2024 eclipse will be a lot closer to home, and I've got my sights set on that oneWell, if you are not coming next August, I'll have to re-adjust my estimate of how many square feet each of us get!!!!Alex
Now THAT'S funny!!!

Beginners Forum / Re: Powermate vs the ES focal extender
« on: January 31, 2018, 01:24:12 PM »
Of course. Maximum field of view is inversely related with focal length (i.e. shorter FL = wider fields, and lower powers).

My 12.5", with a focal length of 1825mm, maxes out at 1.3 degrees, whereas my 4" f/5.4 apo maxes out at nearly 5 degrees!
If you enjoy wide fields, shorter focal lengths are the way to go--you can always obtain high powers with a barlow (and eyepieces
even go down to 2mm these days).

But, remember that if it's an achromatic refractor, you want the f/ratio to be at LEAST 3X the size in inches (i.e. 4" f/12, 6" f/18) to
keep chromatic aberration in check (and preferably 5). A 2-element ED "semi-apo" refractor can be a little shorter, but only triplets and quadruplets
can be made in really short f/ratios and get away with it. Fortunately, some are affordable these days.

If the refractor is to be used for primarily DSO viewing (not Moon or planets), then an achromat can be short, too.
I've viewed extensively with a 5" f/5 and a 6" f/5 and both did fine on DSOs (though both were HORRIBLE on the Moon and planets).

All that explains the popularity of newtonian reflectors--no chromatic aberration.
I used to own a 6" f/5 newt, and I loved that scope. It burned up in a fire, though.

I think that if you just measure the loss of light due to the atmosphere you would be including both absorption and scattering.  The scattering would contribute a small amount to the sky glow - but I think it would be dominated by light from terrestrial sources and airglow from ionized gases in the upper atmosphere.But it sounds like you are somewhat focused on using these quantities to help characterize what a human can actually see at a given location and time.  But that folds in human perceptual stuff - which is a whole can of worms.  It makes sense to do that if you want to characterize a site as optimal for "viewing" - but then it is ultimately a subjective/perceptual thing you are aiming for.  With all the differences in people and tastes - I don't know how that could be done very well "objectively."It's more like describing the best place for a beach vacation.  Many factors and personal preferences involved - some of them are empirical and others are linked to taste and even emotion - and people will differ.Frank

Lots of good info for me, thanks. still haveta go through most of it. I've been clear coating/sanding my dobstuff lightbridge base "kit" the last two days. Two coats of helmsman crystal clear. Going to assemble and then give a third coat before use. Later I plan to paint the lightbridge logo on it in white letters. I'll see how that helps vibrations or not first.

i received and installed the bobs knobs primary knobs and springs, installed and used them last night: BIG difference. Holds collimation accurately at all elevations, barely need the locking knobs. Replaced the secondary collimation knobs with bolts from the hardware store, works fine.

Will ill be going through this list of items, thanks again!

Btw- I noticed on Rob Teeters scopes last week he uses a small metal piece to protect the corners. Anyone know where I can get some of those? I now have two dobstuff bases and those corners do get bumped a lot unfortunately.

I am grateful for the willingness of everyone to help and advise!
I did attend my first meeting of the Albany Area Amateur Astronomists and spoke to our MiSci astronomer as well.
Star Party on Friday was cancelled-due to a lot of snow!

Definitely going to NEAF-it is only a couple of hours south from me.

And I am keeping an open mind as I learn-and considering all options.
And I am looking, looking, looking and listening to all of you-thank you

The current option I am considering is the Celestron AVX 8" with the AVX mount-but wondering if the mount is stable enough?

We have a museum sky gazing event every third Tuesday-so next Tuesday will get to see the 8" Cassegrain and 6" Dob properly set up
(but also will be taking conditions from the Clear Sky Chart into account-a great way to learn how everything comes together to impact viewing).

I am traveling to see the Total Eclipse-with just my camera (properly outfitted).

Concerning the AVX: I've used the AVX often with a 100mm Lunt solar scope tandem mounted with my 80mm refractor, the total load is about 20 lbs. and it handles this setup well. Vibration from casual knocks into the eyepiece settle down in about a second, and wind gusts(probably up to 5 mph)do not noticeably make the mount shake.My usual planet observing setup is my 8" SCT with binoviewer (about a 15 lb. load) on a Celestron CG-5 (AVX predecessor). I more often prefer the planetary views it gives compared to my 16"Dobsonian or 80mm ED refactoreven under the best ofobserving conditions, due to the obvious aperture advantage over the 80mm and the tracking of the EQ mountcompared to trying to track manually at high powers (~300x)with the Dobsonian. I highly recommenda comfortable seat and a binoviewer for planetary viewing; being able to relax your body and use both eyes brings out a wealth detail that is missed while observing while standing, using just one eye/eyepiece.

iOptron wanted me to flash everything. The hand controller flashed fine. I could not connect to the mount to do the main board. I was plugged into the right place on the mount for that.

Advised B&amp;H that I'm having issues. I sure hope it can be resolved with out sending this thing back. Packing it all up would be a real pain.

The hour or so while it worked sure was fun.

I look forward to your meticulous documentation of the focuser replacement. Another item you might want to think about while you take the scope apart is to flock the tube using Scopestuff flocking. The other item I also plan is to add another Vixen finder shoe so I can have a RACI and a red dot finder. I have been doing that to all my Newtonians

It's in my nature to mod things. LOL. I will take pics to document it. It always helps to see how others mod things and I'm sure I'm not the only person who would want to replace the focuser.

I'm going to add my red dot finder as well as my GLP too. I often use the GLP just to show those with me where the scope is pointing as it helps them learn about the sky. I never keep it's just a quick point to the object as a teaching aid and then it's turned off.

I've read where the flocking only needs to be put opposite the focuser. Will you flock the entire OTA? I'm also going to replace the collimating screws on the secondary with ones that have larger knobs and also add a washer to the secondary (like the milk jug washer mod).

Thanks, Don and Simoes!

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