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Messages - buddderpdrivla

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Hi, Alan.Thanks for the picture.

In your previous post, you said that you held the camera up to the eyepiece and snapped the shot of M13. What ocular were you using at that time? Your Parks 25mm Kellner?

As for your 6" f/5 Newtonian reflector, are you fully satisfied with the diameter of the secondary mirror?

Hello Roger,

No, I was probably using a 16mm if not a 12mm.

I tend to favour moderate-to-high powers with the 6" f/5. The secondary has an effective diameter of 48mm. In future, I'll be looking into downsizing it to a 38mm, and so to lessen the secondary obstruction, as I rarely use anything longer than a 20mm with it, if that. I found that practically every time I took it outside, I wanted to ramp up the power almost immediately.

As I see it, I bought a telescope, not a pair of low-power binoculars.

ATM, Optics and DIY Forum / Re: Twyman-Green LUPI interferometer
« on: February 04, 2018, 12:12:49 PM »
I'm still looking for a suitable laser diode for my Bath after testing tens of them..Most of them have an elliptical spot then it is 1mW,3mW,5mW, 10mW?..:)I just experiment with everything .

The only problem with an elliptical signal is that thew narrow part must be wide enough to cover your test optic after passing a diverging lens. Otherwise, you can buy laser diode with a circular beam profile from optical companies such as Edmund Optics but it won't be cheap. You may find the same on eBay for less.

There's also a way to turn an elliptical beam into a circular one using a cylindrical lens. Thorlabs, Melles Griot, Newport, Edmund, etc. and surplus lens suppliers will have what you need. You just place a cylindrical lens of proper focal length in the laser beam and the beam will change from elliptical to circular.

You can also do what Mark Cowan suggested -- use a washer, but be mindful that the beam has to be much wider than the test optic in that case, since the washer will create diffraction at the edges, and that disturbance must not be the part of the beam illuminating the rest optic's aperture.

The IF group suggests turning an elliptical beam to 45 degrees relative to the horizon, because this supposedly gives the best results and higher contrast to fringes. Not sure if that's true.


Light Pollution Topics / Re: Closest dark skies to Orange County CA
« on: February 04, 2018, 10:20:59 AM »

If I am not mistaken, a mountain biker was killed by a cougar not so long ago riding somewhere in Orange County.


Yet no recorded mountain attacks on astronomers that I know of. It's my understanding that these the cats can sense when they've come across anything far to stringy and hard to digest.

Need I say more....?

Mounts Questions & Expirience / Re: How To Check the PE on an AP1100GTO
« on: February 03, 2018, 01:01:55 AM »
I played with PEMPro abit tonight - but I was in/out of clouds so nothing for good data. I have a question though:

What camera should I be connecting? I connected with the ASI1600 through SGP, but it looks like I could use my Ultrastar via PHD2? Does this matter?

Also, if I select "PEM enabled" then is it using the PE curve that is currently loaded/correcting in the mount? Where is that PE curve kept? Can I have access to it to see what it looks like in PEMPro?

I am using the current Beta 3 - I guess this is the one to use vice the V2?

Beginners Forum / Re: Help needed buying Omni XLT 150 OTA
« on: February 02, 2018, 09:56:08 PM »


I pulled the trigger, I just couldn't let this deal pass me by. At $349 with OTA and CG-4 mount, its a steal at this price.

Yes, now let's hopeour orders gets processed and they haven't actually run out of stock. I had one experience where only a Dob mount was shipped and the OTA never came through, the retailer ran out ofthe OTAs!

I am a high school Physics/Engineering teacher at a small PBL based high school in Evansville, IN. (http://www.evansvill.../real-world-now) In my teaching experience of 31 years, I have introduced students to Astronomy with borrowed telescopes or telescopes that I have picked up at yard sales. ( http://www.cloudynig...-i-ever-spent/) That first year I showed students sunspots, and the rings of Saturn; one of those original students became a science teacher and is now my principal!

I got away from Astronomy for several years but got the bug again last summer after finding that RV-6 last summer. I have started an Astronomy club at our high school and have recently acquired a Celestron 8SE from a donor. The kids and I are very excited, but the weather has been rotten for some time. However, with the solar eclipse coming in August of 2017 we have a unique opportunity as we are only 70 miles from Hopkinsville or Princeton, KY which will have a 2:40 second duration of the eclipse. We plan to take all of our students to experience this once in a lifetime event, but I want to them to see this in a number of different ways. This is where I need your help, and the members of Cloudy Nights have been more than helpful on several occasions in the past.

I want to purchase a dedicated solar scope (Lunt or Coronado?) , tripod, a video camera, and a solar filter for the 8SE, along with several Sunspotter Solar Scopes. What equipment would you recommend for this? Is there anything that I should be considering?

I have a number of goals with the Astronomy club’s future:
1) To get my students comfortable enough with the telescopes so they can do outreach programs at other schools and with adults.
2) To build an observatory so the school can have access to the telescope from their computer at home. Our school is in the Career and Tech Center and the students have the ability to design and build the observatory under one roof. (http://www.edlinesit..._Programs/SICTC)

Beginners Forum / Re: Hello all, New member and first time solar question
« on: January 31, 2018, 09:22:56 AM »
I have a white light filter for my Omni XLT 120 and its basically the same as buying a welding helmet. I have used it to image events like the 2012 Venus transit and several partial eclipses. It also is fun for viewing sunspots. I have always wanted a hydrogen alpha scope though and over the last few years I have continued to look into the right one. I really felt like I had decided on the Coronado SolarMax II 60 with the 10mm Blocking Filter. Would love the Double Stack and 15mm blocking filter but not sure if I could ever afford it.

The PST will probably be the one to get since I finally realized that the SUN is really BIG and CLOSE so aperture really is not a huge factor. Not like you cant see the sun naked eye or something. Also they must be really good because you rarely see them for sale on here which leads me to believe people don't get rid of them.

Let us know what you get Cameron.




I understand that this is annoying, but I'm not sure it would cause any problems, especially in declination. How does the mount do on that axis when guiding, or just for goto?

my feeing is that it is causing excessive backlash in DEC, but I am still not 100% sure. If that is the case that is something than can probably be worked around, and most lower end mounts have this issue I guess. Doesn't really reflect well on the manufacturing though, just looks rather cheap.
I don't see how this could cause backlash. As long as the belt is properly tensioned and--far more important--the final gears are meshed correctly. Most backlash comes from those final gears, not transfer gears nor a belt.
My reasoning at the time was that if the gear is wobbly, there will be times when the tension becomes uneven. The more I look at it in action though I think the backlash is coming from the motor rather than the belt.

Beginners Forum / Re: The reason I don't have a Dobsonian
« on: January 31, 2018, 05:36:27 AM »

I am not a great fan of Dobs but they have their place due to the cost but I dont understand a 8inch dobs is no heavier than a 8inch newt on an EQ5 mount (much better set up in my opinion) so the shipping costs should be similar

In an 8 inch, a Newtonian mounted on an Equatorial mount is reasonably doable. There are additional hassles, the fact that the tube rotates as one moves across the sky means the tube must be rotated as one moves across the sky and that the viewing position can be quite awkward.

But as the aperture increases beyond 8 inches, Newtonians mounted on a GEM (German Equatorial mount) become more and more impractical, the mount requirements increase dramatically, the observing becomes more and more awkward, ladders are required. Transporting them and setting them up becomes much more challenging. This photo tells the story. One scope is an 12.5 inch F/4.06, one is a 12.5 inch F/6. That is a difference but the real difference is in the mounts. One of them has traveled throughout the southwest, one of them never made it more than about 25 feet from the garage.
I can setup the 22 inch by myself, it took two people to safely setup the 12.5 inch on the GEM.

Agree 100% 8 inch is about the most I would use , I used to have one but changed it for a 6 , for really large aperture on an EQ mount one cant beat SCT, I only mentioned this due to the shipping costs

Aleko.,,I can make a list with SSplus but I don't.,I just look at the different colors of the stars on the chart,and hop my way from one to the next.,It's nice to do it like this because I stay in the same area of the sky.,use the same EP.,and get to see lots of sights along the way.,Learning to star hop has been a very enjoyable task lately.,and I'm getting lost less and less each time out.,

I'm with ya Dave. Even from my light polluted driveway, I find it much more enjoyable and rewarding finding my way without setting circles etc.; haven't used them in over a year. I do like the SF downloadable lists though, as they give me a starting point. In this case I'd miss a lot of interesting carbon stars without them.


Beginners Forum / Re: New Guy, New Scope
« on: January 31, 2018, 05:14:55 AM »
Joe, I'd pass on all those you listed. But there are two on CL that you didn't mention that I would consider for camping and quick sessions anywhere.

There's that Orion 80mm refractor for $100, or the Celestron 102 GT for $200. (Ignore the other ad for the same scope asking $300)

Don't know if you wanted GoTo but you might offer $150 for the second one. I once had the 90mm version and was pleasantly surprised by it.

Beginners Forum / Re: Hello Im New. Im Stuck already !
« on: January 31, 2018, 04:32:54 AM »
Yeah I thought that and shipping was aprox 100-150US and my government was gonna sting me $200-300 aus stamp duty tax ! Buggers.Only3 shops in Australia for the stock 8se price new in US $2241.00pickup  or $1870.plusshipping from east $1720. plus shipping from east. 1 place sold 8inch sct OTA and that's $ 1350 US. plus shipping.

I've studied reviews on the 8se for a while and so far the cons for it are mainly concerning AP use. And the OTA is pushing the mount to its limits. I'll see you in the Mount forums hehehe  and back here with sum pics.

Beginners Forum / Re: Help with constellations
« on: January 31, 2018, 04:09:47 AM »
There are MANY good books to choose from. The one I started with is "Audubon Society Field Guide to the Night Sky". It has charts for the zodiac, charts for N and S hemisphere, for every month, for every constellation, - essay's for every constellation, solar system, color plates of many objects, and charts include all Messier objects and many NGC objects and items of interest. Essay's include lore and history and itemize the named and main stars and objects in each constellation. It is an inexpensive and great book, - small and easy to use, and can fit in a large pocket. For it's convenience and wealth of info, it is still my most used astro/book. Vinyl cover is water resistant though not the pages. It's like a old worn comfortable shoe that just feels good for grab and go. Thomas M.

General Astronomy & Observing / Re: Purchase regrets?
« on: January 31, 2018, 12:59:19 AM »
Not purchasing regrets, but selling regrets. Should never have sold any of the following: 1) My first telescope, a Tasco 60mm; 2) A fine little 60mm Unitron equatorial; 3) C8 XLT on the Super Polaris

I did not regret selling the Meade LXD-55, however!

Never did let go of the mirror from my old 8-inch Newt from when I was a teenager though, so I still might do something with that!


And here's one of the things that made my brain hurt - in the photography world, the higher the number on a lens, the greater the magnification. A 10mm lens would be a fisheye, while an 800mm lens would be a serious telephoto. Now I start reading all of the posts about eyepieces, and it looks like the larger the number, the lower the magnification.

This is why I ask the questions....

I’m pretty new also. Remember magnification is focal length / eyepiece diameter.
No, magnification is focal length of telescope / focal length of eyepiece.

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