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Topics - sdelbapaglo

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OK, how many of you have eyepieces that "overlap" or "duplicate" other eyepieces...and I don't mean bino-viewing pairs? And do you keep them because they fulfill different purposes (like an outreach set vs. your own home set), or because the views/framing are different, or for other reasons?

As an example, I have several of the ES 82* eyepieces, but not the 14mm. I am considering buying the 14mm, however, even though I have the 14mm 100* and the Panoptic 15mm. The 12.5mm and 14mm Morpheus are also calling my name. Is this crazy? Will I get them and find myself just using one in that range (probably the 14mm 100*), leaving the others just to sit there? Or, will I find that using the 1.25" eyepiece is better suited (balances better) for my 80mm APO on an alt/az, saving the 100* for the 4" APO on a GEM or the 8" fork mounted SCT? Or, find the 100* is overkill on some DSOs and the 68* Panoptic frames them better?

Another example...ES 20mm 100* (or Ethos 21mm) vs. ES 20mm 68* (own this one) vs. ES 24mm 82*, and we could throw a Pan 22m or 24mm into the mix as well. Just one of the bunch, or is there value in owning a couple of them?

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Hey all,

So rooting around in a garage, I found an old Orion StarBlast 4.5 kit, complete with the EQ mount and everything (manual controls, etc). I immediately discarded the mount as its totally junk and wobbly which is why this thing sat for so long. The tube is in good condition, was covered, capped, etc, mirror is clean. Everything still works smoothly. Figured, maybe I can make this little guy good for sure for a Rich Field telescope, being such a short focal length with a decent aperture and weighing nothing. It still has its rings. It has its focuser (1.25").

I just ordered an 8" dovetail to mount it on and it will be ready to use immediately.

Things that strike me right away:

1. Focuser is total junk. It works. But it's not metal. While it will be ok at low powers, it will be hard to deal with at higher powers. This may not matter at all. It has no focus lock either, so a bump will send it out of focus. I would love to change this focuser out with anything else, something metal and with a focus lock. But my google-fu shows this is either not happening without custom work, or basically it's impossible and these scopes are focuser-handi-capped. I'm ok staying 1.25" on it. I'd love 2". But I realize that's not happening.

2. The old EQ mount is totally junk, I didn't even take it. I will use it on a Twilight I for right now. But I'm thinking of getting a Twilight Nano ($80) later on to use it with (since they market their similar size/weight reflector with the tripod, maybe it will work out?). Anything is better than the stock EQ mount it had. But, I want an inexpensive alt-az mount for it. So I'm looking at the Nano, or maybe the Celestron AstroMaster mount. Something cheap. It doesn't have to be ultra-steady, just functional.

3. Not doing a red-dot or anything, I'd rather use a RACI I think, or a laser pointer. I'm tired of trying to bend over and use anything that requires you to look through it other than a right angle if it's pointed up. I have a Telrad, but I don't want to get down on all fours to look through it either. RACI is probably the only way I can tolerate going. Otherwise, laser pointer is faster. I will try both maybe as I have them.

Any advice on anything I can do to make this scope work well?
Worth even doing anything with it?
Not interested in making it top notch. Just thinking rich field, moon, etc.

Very best,

3
Reflectors Telescopes Forum / Aperture mask
« on: January 01, 2018, 07:59:27 AM »
I need help wrapping my head around this:
When observing in less than great seeing, why is it preferable to reduce the aperture via a mask than just use a lower power eyepiece; brightness?

4
ATM, Optics and DIY Forum / need help building a tracking platform.
« on: December 30, 2017, 12:55:47 PM »
I found a scope I want to buy but its a big one. Its a 16"f7 I plan to use it for planetary and lunar images. You can visit the solar system imaging section if you want to see my images from a wee 6 f8. I don't really wish to buy or build a giant gem I was looking at the world mount for sale in mounts but to tell the truth I have had my experiences with large gems they are heavy and hard to set up and move around + a good pair of buyers gears + the mount will be way to expencive. I am prety hard on my equipment and I would rather build a platform then go out and spend 2000+ on a brand new aluminum traking table. so enough explained
I have years experience in aviation mechanics/ industrial machinery/ even optical shops grinding and polishing prisms and flat work for industrial purposes. I have a high level of mechanical experience and can build anything but there is one thing that i still find confusing is the tracking platform. Is it possible to build one fairly cheap with dual axis and slew or say 2 speed slew- slow and medium for centering planets and close up lunar work ?. and is there a site or plans that show links on where to buy drives bearings and so forth. I am still even un clear on how the upper platform is connected to the lower platform on the polaris side/ north side or what ever you call that part of the platform. if I actually got to see one then it would be easier to understand how to build it. I am still contemplating a fork mount with a 2" shaft with a .5" hollow for a polar scope its much simpler.
any help or links to parts or plans would be help full thanks

5
Reflectors Telescopes Forum / Orion XT12g: First light
« on: December 29, 2017, 05:01:52 AM »
Finally had a chance to get my new Orion XT12g out last night, my first dobsonian. Got a late start, ended up trying to align the finder, doing my first in the field collimation and then star alignment in the pitch dark. I managed to achieve decent collimation, maybe 90-95% of perfect, but I struggled with the go-to alignment. As I said, I got a late start and was totally not prepared, so here I am reading the hand controller manual in red light out in the 15 degree cold .  After getting nowhere for 30-40 minutes I gave up and decided to just slew to some easy targets manually before the clouds rolled in (at this point I'm about 95% sure this was user error). Ill update once I actually know what Im doing here.

First target: m42 (44x, 1.5º)

Whoa! I've been viewing this a lot the past few months from my 80mm ED doublet and I thought that was impressive but wow! The first time I approached the EP I noticed it was projecting out this blue-green glow that lit up your whole face from a foot away, I couldn't believe how bright it was, and what a beautiful color. I was able to see much much more structure and detail then I had seen yet. Dark dust clouds actually looked like something instead of just being the absence of light like I see through my 80mm. Awesome!

M81 & m82 (44x 1.5º, and 115x .7º)

I was able to fit both in the FOV with my 34mm ES68. This is another target I have recently viewed through my 80mm. In the low power EP they showed noticeably brighter than through my 80mm but not drastically so. M81 was definitely more extended. Going up to 115x the gap between the XT12g and 80mm got a lot bigger. M81 was more or less still a hazy oval with a bright core, but a lot bigger and still fairly bright, but at this magnification I was able to just make out some structure in m82, particularly some dark areas near the center. Very cool as this is pretty much the first detail I have been able to see in a galaxy (beyond seeing the core). This was impressive through the XT12g, but I have to say my SV80A did very well on these at low powers considering its obvious light gathering disadvantage.

Jupiter 115x and 166x

I wasn't even going to do it because it was low on the horizon (~20º), right over my poll barn which I figured would effect seeing, I wasn't sure how accurate my collimation was and I had my doubts that the mirror had got to temp but I ended up checking it out anyways on the request of my viewing partner and boy was it a pleasant surprise. at 115x it was glaringly bright but fairly sharp and contrasty with all kinds of details and color evident. At 166x I was treated with my best views of Jupiter yet! I was able to get glimpses of details within the belts for the first time including festoons. I have to say I wasn't expecting this scope to be great for planetary but I was really impressed with this first viewing.

Comments:

Considering the circumstances I was really impressed with this scope optically. So far my experience has been small 80-90mm scopes and an older Celestron Nexstar 8i SE and the XT12 seemed like a very worthwhile upgrade from both of those. Compared to the smaller scopes (including my current SV80A), I just couldn't believe how much brighter the view was! Obviously at 12" its a heck of a lot bigger but I read some comments of people saying its not that much different and I tried to keep my expectations reasonable but it really is a huge difference, even from the Nexstar 8.

At one point when I was trying to do the go-to alignment I was panning around looking for Betelgeuse which Im very familiar with through my 80mm, I kept seeing stars and thinking is that it? Maybe, thats it... and then holly crap, that is definitelyit! I just couldn't get over how bright it was and it seemed quite pinpoint too.

Compared to my old Nexstar 8 the XT12 IS noticeably brighter, but not only that, it seemed to have a darker background and more pinpoint stars. To put it simply it was just a much more pleasing view. If I where to put it on spectrum of image sharpness and contrast I would put the XT12g between the Nexstar 8 and my SV80A, but closer to the refractor.

Build/construction I would again put it between the two, but closer to the Nexstar. The focuser on the Nexstar drove me nuts, the XT12's is much better. Tracking on the XT12 was noticeably more accurate than the Nexstar 8i SE too. Fit and finish and QC are admittedly pretty poor. I definitely had some minor issues right out of the box.

Size wise, Im not going kid anyone, its big. I could probably carry it myself in two pieces but I wouldn't want to go far with it. With two people and two pieces its an easy carry. With two people its doable in one piece, but again, I wouldn't want to go far with it like that. Ive yet to try and load it into my SUV in one piece with two people, but I think this is going to be pretty difficult. My first mod is going to be wheels and handles which should make it an easy move for 1 person.

So far Im happy I went with the solid tube version instead of the truss model. I can't really foresee any situations where I would need to break it down any smaller (it fits in my SUV as is) and having it in one piece ready to go in my poll barn is priceless.

Potential concerns:

Obviously the go-to, but like I said I think this was user error on my part, time will tell how well it works.

The focuser did slip a little when I was using the ES68 34mm. I had recently moved the scope from my warm SUV to the 20º outside though, and Im wondering if thermal contracton had something to do with it. If not, the ES68 34mm is a heavy EP and the focuser my require some adjustment right out of the box.

This is my biggest concern at the moment. ALT drive slippage, when I was viewing Jupiter low on the horizon with a light weight t6 EP the scope was struggling to slew down in the ALT axis so I ended up moving it manually. I could hear the motors spining, but the OTA wasn't moving. Once I got it in the FOV it tracked it fine. I don't think there are any user adjustments to the ALT drive so hopefully this was just an anomaly. Im not sure why the OTA would be out of balance. Any veteran dob users care to comment on this?

Will update as things develop but I have to say so far Im impressed, particularly with the optics.

Next up, star test!

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General Astronomy & Observing / Purchase regrets?
« on: December 29, 2017, 02:17:23 AM »
Hello everybody,

Gonna steal this one straight from our friends at Astronomy Forums but I wanted to know, given your experience, what equipment would you not have purchased if you could do it all over again? Can be anything from a Scope to just equipment. This can help to weed out stuff that's not needed so other members don't make the same mistakes. For me, I would say my original scope, a Meade 114mm EQ which was terrible and broke on me. Due to that I have not to this day bought from Meade again and I don't think I ever will. What about you guys?

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Greetings Everyone,
In 2005 I took a class from John Dobson (telescope building in Monmouth Oregon) where I built a 10" scope.
At the time I worked at a semiconductor factory and managed to obtain a stack of 14+" fused quartz disks.
Some were pretty beat up.

I brought a few to John Dobson and gave him one. John picked the worse one of the bunch. When I asked him about the big chips out of the edge, he told me the blank was also missing a piece 3 feet away from the mirror. He said the missing piece wouldn't matter.

John worked on grinding that mirror for a month. He didn't make much progress. I was checking out CloudyNights.com, sometime later, and I saw Carl Zambuto and John Smith presented a beautiful mirror to John Dobson. The story was that they had met up with John Dobson, I believe in Monmouth, and offered to figure the quartz disk for him. The beautiful mirror was the end result.

All that to say I still have a stack of these disks. I have 18 in all and a couple 10" disks also.

Here's my dilemma. I am now into lapidary. These fused quartz disks have value in lapidary as optically pure coverings for triplets (usually opals). To use these in lapidary would mean slicing them up into thin pieces.

It seems like a terrible thing to do to a good fused quartz mirror blank. These disks are 14-11/16" in diameter and .800" thick. How much are they worth as mirror blanks?

Thanks for your opinions.
Glen Ray

[email protected]
<p class="edit">
Edited by ausastronomer, 22 January 2017 - 12:23 PM.

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Beginners Forum / 2" vs 1.25" EP
« on: December 24, 2017, 06:39:24 PM »
Hello,

I own a Nexstar Evolution 9.25 and that I really do exclusively visual observation on it.

I noticed that the exit entire of this scope is larger than 1.25" but smaller than two".  So my question is will I benefit in updating the star diagonal to a 2" and obtaining two" EP with this scope?
Will I gain in TFOV?  Will the image be brighter?  I understand that ultimately the maximum TFOV is inherent to the scope design but will I increase it bu updating into two" setup?

2nd question: Suppose that I decide to stick to a 1.25" set up, is it worthwhile to upgrade to a greater star diagonal that the one already provided by Celestron?

Again I just do visual and love to look at everything from planets to DSO.

Thanks.

10
Would theCelestron 12V 7 AH Power Tank be enough to have the HEQ5 track an object for 5 to 6 hours throughout the night for AP?
The slewing would be restricted to aligning the extent and framing the object.  It would be only tracking after.
Would the electricity tank last that long?

Anybody with experience with these together?

Thank you

11
There appear to be a vast array of tabletop telescopes.  Some are on small tripods.  I've seen a tabletop EQ mount.  But most appear to be a variation of this Dobsonian AltAz mount.  Most appear to be fairly short FL reflectors or refractors thoughI have observed 90 millimeter Maks within this arrangement.  All are manual but I have observed a couple of tracking mounts and at least one that may be GoTo.  When I first started in the hobby, 18 months ago, I nearly purchased a tabletop refractor.

<strong>I am not here to begin a debate or to advocate 1 way or the other.  I am here, as a relative newcomer, to find out.  So I would love to listen to the opinions of OWNERS or even FORMER OWNERS or individuals with extensive personal experience with these programs.  </strong>

When I read comments on such methods I get both extremes.  So I wish to understand the actual story.  I might want to have you to add to my equipment or that I might consider advocating one to a friend on a budget or with limited space to store a range.

Here is what I read:

Some love them for their
Small size and convenience.
A true grab and go scope that are easy to plop down and use
Low cost for the aperture
Great travel range for family vacations
Some dislike them
You Require a table or some strong to sit them on
On a table it can be difficult to maneuver around these to point at your targets and use the eyepiece
Utilizing the finder scope can be near impossible

Obviously a few are dirt cheap and perhaps inadequate quality however there are a few which are in the $400+ range and according to strong optics.

What do/did you love and what do/did you hate.
Can you recommend one to a friend
Do you still have yours?
Would you buy another?

Inquiring minds wish to know.

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