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Topics - stimtinpaso

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Most of us, whether we recognize it or not, live in locations where the influence of the jetstream and winds aloft in general is a variable and important influence on a night's potential for observing.

Do you monitor those conditions and factor them into your decisions?

ATM, Optics and DIY Forum / 10" F4 collimation
« on: December 31, 2017, 10:30:06 PM »
Just got the first images from my new home made 10"F4 scope. I am new to a fast Newtonian and the collimation seems off substantially. Out of focus stars look pretty bad. The large 3.6" secondary leavev a large hole in the center but the out of focus stars are not round.

I used a Glatter laser with a Parallellizer and a TUBLUG.  I first centered the secondary under the focuser with an 8" long 2" diameter sight tube. I then used the laser and the Parallellizer to hit the center of the primary by adjusting the secondary holder. After this was done - I installed the TUBLUG and laser and put the primary shadow of the center dot on the target on the TUBLUG.

Did I do it correctly or should I have done something different?

I may need a smaller more precise center dot to be more accurate.

I think I bit off more than I could handle for the first attempt. I was using a Parracorr for he first time also. I think the scope will be a good one but I have a ways to go.

Just about everything went wrong - The Loadstar 2 (for the first time ever) was flaky and constantly locked up TSX until I gave up guiding. I tried to shoot a few flats and got some strange donut shapes that look like and unfocussed star. They are obvious in the image. My autofucus program did not like the donut shaped fragmented unfocussed stars and did a poor job. I have attached about the best that I could do - 20 - 60 second unguided lights with a quick stretch in PI. Not even sure what the target is. I clicked on it in TSX and don't remember what it is.

Any comments and help would be appreciated.Attached Thumbnails

This post is to emphasise the importance of shining a bright halogen light down any new EP you buy (or second hand EPs really).

Shine the light down the eye lens, look up through the small nose lens at an angle so the halogen light bulb is out of sight and slowly rotate the EP. Look for:
- large dust specs in the optical path,
- scratches on any of the lenses, and
- chipped edge to any lenses.

Whether these impact the view materially is not an issue; if it's new it shouldn't have any such fault.
The following 3 faulty EP experiences were found using the halogen light and *all 3 were premium brands.*

1. This is the most recent and prompts this post. The unmentioned brand was bought yesterday and oops! looks like a scratch to an internal lens was caused by glass-on-glass impact. It's sent straight back and a replacement is coming.
(Please don't mention the brand if you recognise it; mistakes can happen and it's quickly being remedied).2. The 2nd was a used Pentax XW10 bought on here from a US CN member; the halogen light test showed a 3mm speck of dust right in the middle of one of the internal lenses.   Rather than posting it back from the UK with high postage cost, I sold it at nearly half the price paid, after mentioning the fault in my advert. A shame because XWs are normally very good with dust control.

3. The 3rd was a classic. Bought a new EP direct from a top brand manufacturer, but the nose lens was so scratched it looked like it had been a hockey puck in a former life. The owner said "really sorry, post it back and we'll send a replacement EP."
He instead just swapped out the nose lens/ lower assembly... and this new nose lens now had a chip to it's edge!
The owner said "Well, it's not in the optical path so there's no impact on views (no glass strain being released, no light scatter?), but you can send it back at your cost and we'll replace it."
I could no longer trust that guy.So with your next new EP purchase, please use the halogen light trick and if it has any of these faults mentioned, take photos and send it straight back.

Eyepieces Questions & Recommendations / The 2" 2X Barlow Choice Dilemma
« on: December 29, 2017, 01:55:58 PM »
I have somewhat of a dilemma. I love my ES 82 30mm as its about the easiest eyepiece in terms of eye placement and comfort for my observing style. It seems to be a very well matched eyepiece to my C8. My other eyepieces are a 22mm Olivon (also super easy eye placement) and then I have a 14mm Baader Morpheus, ES11 82 and then a Long perng 9mm (Levenhuk ER20). The Morpheus is a little more time consuming on eye placement.

My only experience with barlow lenses has been an Orion Shorty 2X barlow so I don't have much to compare to.

I'd like to experiment with barlowing the ES30 82 as its eye placement is so much easier than the Morpheus. I'd also like to see how the ES11 82 does.

My main question is:
-If I get a good barlow would using the ES30 82 render the Morpheus obsolete or am I still going to get a "better" view from a 14mm without a barlow?

I've started the Astronomical League Globular Observing Program and really like the views in the ES30 82 but would like to get a little more magnification to see some more detail.

Also i'm searching a few barlows and wondering which you'd pick. Try and be objective as possible

Lowest cost:
GSO 2X Barlow with 1.25 Adapter $70-80 shipped depending on which re-label branding

Middle of the Road
Explore Scientific 2X Focal Extender ~ $214.99

Highest Cost
Televue Powermate 2X 2" ~ $309.50


ATM, Optics and DIY Forum / I did a dumb thing and need advice
« on: December 29, 2017, 12:22:29 AM »
I was careless the other night putting away my Meade 290 mounted on a Twilight I. I keep my scopes in my garage and collapse the legs to go through the man door. In the darkness I spread the legs to stand it up again but did only 2 of 3. After the loud bang I turned on the lights to see it lying flat on the concrete floor. The damage was not too bad. The low end diagonal was broken as were some screws on the finder scope. The aluminum dew shield has a slight flat spot. What is bad is that the black ring which holds the objective lens and screws on to the ota is askance. It is now cross threaded. A photo is attached. So how best to get it off and straightened without damaging the threads anymore? I’ve tried unscrewing it but it does not budge.If there is a better forum to list this under I'm open to suggestions.

Reflectors Telescopes Forum / LP and 8" Dobs
« on: December 28, 2017, 04:18:37 AM »
Hello There. My brother is thinking of purchasing an 8" Dob to get into the hobby.

I was wondering if this is the best option for him considering that we live in a yellow LP zone. I'm concerned that the LP will be overpowering for the scope but I really don't know what to expect. My scopes are small refractors.

If LP is going to be an issue, are there any "work arounds" like filters and such.Thanks,
Pirate Mike


ATM, Optics and DIY Forum / 16" f/4 Tensegrity string scope
« on: December 28, 2017, 02:36:15 AM »

I would like to share details of my 16" f/4 Tenesegrity telescope which I built slowly over the last 4 years and debuted at Oregon Star Party this year. It was also featured in Mel Bartels' Telescope Walkabout..

16" f/4 Quartz mirror, 1" thick / 15 lb - by Mark Cowan
3.5" 1/20th wave Antares Secondary
Wire spider
Tensegrity String Telescope design based on Don Peckham's design and Dan Gray's original string scope design
Strings are 10 loops each of UltraCam bowstring material and covered with Slink-drifter tubes
Dan Gray's Sidereal Tech Drive System with clutches to manually move scope
Optical tube assembly weight - 49.8 lbs (includes paracorr II, 20mm100 ES eyepiece, Stellarvue 50mm finder)
Rocker box + ground board + motor drive mechanics - 23.5 lb

Lots of people helped with ideas and inspiration that I would like to acknowledge - David Nemo with his 20" string scope, Chuck Dethloff from whom i borrowed a lot of the drive system ideas, Don Peckham, John Delacey and many others at the Rose City Astronomers Telescope workshop for ideas and help with tools, Dan Gray for help with the drive system and Reiner Vogel's excellent telescope making website with lots of ideas and inspiration. Also Albert Highe's books on telescopes and string telescopes are a great resource.

In general I am very happy with how it turned out and how rigid the assembly is.. Vibration damping is excellent - something I was worried about. I am posting several pictures below !

I do need to work on the clutches - the telescope doesn't move as well by hand..


Assembled Scope

Eyepieces Questions & Recommendations / Figuring out Barlows
« on: December 28, 2017, 12:20:16 AM »
My only experience with a Barlow has been my 2X 4-element ES telecentric.Through my reading in these forums, and also 'Turn Left at Orion', the wider the AFV of an eyepiece is, the worse they Barlow as a general rule. After I started to figure out the hard way did I see how well my 68* ep's took a Barlow compared to the 82's.
As much as I like the 4-element Barlow, they are just really heavy for my small scope. I decided that I would settle for a 2-element Barlow, and the goal was a TeleVue 3X. Well, being cheap, and seeing as I already had the loot in the account, I settled for a GSO 3X. I know, I know, but this 3X Barlow thing is also the start of an experiment for me.
With the advent of the Delite and ES 62's, maybe I'm on to something here for myself. Any comments on how you use Barlows? Anyone Barlowing these two particular lines? Clear skies, Mark

General Astronomy & Observing / Observing vs imaging existential crisis
« on: December 27, 2017, 12:12:55 PM »
I love observing, and have never really considered imaging because of the time commitment and financial investment to get *good* equipment.But then I saw this image of M42, which is probably the most aesthetically pleasing astro image I've ever seen.Now I don't know if I want to invest further into observational astronomy, or go full tilt into imaging. I don't have money for both!Anyone else have to make the decision where they wanted to sink their astro-dollars?

General Astronomy & Observing / NGC 5139
« on: December 23, 2017, 11:00:35 PM »
Has anybody in NY (43* North) ever detected Omega Centauri?  Or are we simply too much North?  I've read this is the prime time of year to see it but I've always thought it is too much South.

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