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Posts Made By: John Roehrig

February 26, 2007 09:02 PM Forum: Beginning Astronomy?

Telescope for low temperatures

Posted By John Roehrig

I have a friend who is wondering about what scopes function well at low temperatures. She lives in Alaska and is just getting into the hobby. The temps she deals with might reach -20 F. My initial recommendation to her was to get a refractor.

What say you?

John R.

August 29, 2009 07:08 AM Forum: Refractors

AstroTech 66ED Refractor information

Posted By John Roehrig

I have been looking at this little scope for quite a while as a "very" portable scope option, but I have seen very little written on them - or at least not found the right place for the info. Does anyone have experience with these scopes? For a frame of reference, I have owned a Televue Pronto, TV-85, and Orion 80mm ED. My current grab-and-go set-up is the AP Traveler with a Vixen Porta-mount or TV Gibralter (not quite a grab-and-go scope). Don't get me wrong, I doubt that the 66ED will be as good as the TV or AP scopes, but it looks appealling as the basis for a very small set-up.

Thanks in advance,

John

November 24, 2002 09:39 PM Forum: Equipment Talk

Pronto Purchase Question

Posted By John Roehrig

Andrew,

I'm not sure the OTA only Pronto comes with the clamshell. Buy used looking for a Pronto without the diagonal.

John R.

December 11, 2002 04:35 PM Forum: Equipment Talk

Best Wide Field Eyepiece

Posted By John Roehrig

Hi David,

This reply is a bit late in the string, but I have gone down this path, too. My current bullpen of EPs for my f/10 Nexstar 8 is: TV 55mm Plossl, TV 40mm Plossl, TV 35mm Panoptic, Apogee 30mm Widescan, TV 26mm Nagler T5, TV 22mm Panoptic, TV 17mm Nagler T4, TV 13mm Nagler T6, TV 9mm Nagler T6, 2" TV Big Barlow. I have shorter F.L. EPs, but 9mm is about the limit for the N8.

Before acquiring all of these, I had a Celestron f/6.3 reducer/corrector, and used a Celestron Ultima 35mm EP for widefield views. This EP gives one of the largest FOVs for a 1.25" EP. I loved it. The 35mm has very long E.R., but a simple EP cup from Orion solves the problem of eye placement.

In reality, however, the 2" EP is the way to go. I have since sold my 35mm Ultima and f6.3 r/c. The problem with the r/c approach is that you need to remove it for higher power viewing. This is not convenient since it screws on the visual back. You can get a Celestron 2" SCT mirror diagonal for not much money, and having it opens up a new "vista" for you.

My personal EP favorites for this scope are the TV 55mm Plossl, Apogee 30mm Widescan, and the TV 26mm Nagler T5. I do not use the 40mm Plossl or 35mm Panoptic very much with the N8. For best FOV the TV 55mm Plossl is hard to beat at the price. Used ones are always for sale on A-mart at a reduced price.

John R.

December 21, 2002 06:38 AM Forum: Equipment Talk

Eyepieces for an 8" f/10?

Posted By John Roehrig

Hi David,

You have received many good suggestions. I have the Nexstar 8, f/10, and have some premium EPs, so I'll just throw in my two cents worth. Bob Black opens an interesting point about the Barlow. I have a TV 2" Big Barlow that I first got hoping to avoid the need for so many EPs. I got away from using it, because I didn't like having to switch it in-and-out all the time. I now have a full range of EPs, mostly Naglers or Panoptics, including the TV 3-6 mm zoom EP that I use on my TV 85mm. As I have gotten more experienced with these scopes and EPs, I find myself using the Barlow again more and more. I do not find much degredation in the view, and I like to keep the FOV, clarity, and contrast of the Naglers, rather than switching to a lower FL EP. Anyway, the Barlow decision is a big one!

For my N8, if I had to choose three EPs to use with a Barlow, I would keep my TV 55mm Plossl, TV 26mm Nagler, and TV 17mm Nagler. This would give me FLs of 22.5mm, 13mm, and 8.5mm with the Barlow. I am not a big fan of the 35mm Panoptic (but am probably in the minority). For the N8/C8 I really like the 55mm Plossl for its FOV.

John R.

December 23, 2002 10:25 PM Forum: Equipment Talk

Orion's new mount

Posted By John Roehrig

Hi John,

I have three mounts: the older version Orion Skyview Deluxe, a TV Panoramic mount with a Telepod, and a Bogen tripod with a Telepod. I had a TV Pronto and now have a TV 85mm. My impressions are as follows:

1. For the Pronto, the Telepod/Bogen was excellent. A very lightweight grab-and-go set-up. The Skyview was overkill unless I wanted to track. Even though it was overkill, the EQ mount, slo-mo control, and tracking motor makes it very useful, even for a smaller scope like the AT1010.

2. For the TV 85mm, the Telepod/Bogen is not solid enough at high powers, but I will still use this set-up for travel. The Panoramic/Telepod handles the 85mm well, and is recommended by TV for it. This is what I use most often at home. The Skyview also handles the 85mm very well and is very solid. Its only slightly less convenient than the Panoramic, and I often prefer it for its superior tracking due to the EQ design and the slo-mo control.

So, I think you first should decide what you will do with the AT1010 (which is very close to the Pronto) and if you want an Alt-Az vs. an EQ mount. If your want a grab-and-go scope consider the Telepod/Bogen. If you want easier tracking on an EQ mount, but a less portable tripod go with the Skyview. The larger mount/tripod will also better accomodate your larger scope - when you eventually trade up!

An alternate would be to look for a used Skyview Deluxe on Astromart and a used Telepod/Bogen set-up. You would probably end up with two mounts for the price of one. All of the aforementioned scopes and mounts were acquired on A-mart and are top quality.

Good luck!

John R.

January 14, 2003 07:12 PM Forum: Equipment Talk

2 inch Visual Back for 8" SCT

Posted By John Roehrig

Debbie,

Anacortes sells a Televue adapter for SCTs for $45.00. This screws onto the back of the scope and accepts standard "refractor-type" diagonals. I have one and it works well. You can also buy from Meade or Celestron a 2" SCT diagonal that screws right on the back of the scope. I'm sure that Anacortes has these as well. Since I don't know your type of mount, you must be sure that the "adapter-diagonal" set-up will clear the base at zenith. This is usually not a problem with the screw-on SCT dedicated diagonals.

John

March 15, 2003 08:29 AM Forum: Equipment Talk

C11 vs Starmaster 11

Posted By John Roehrig

Another thing to consider is weight. The C11 GPS is a large scope that requires lifting the OTA onto the mount. The mirror box in the the StarMaster (and other big Dobs) can also be heavy - although I doubt the 11" would be too bad - but you don't have to lift it very high to get it into the rocker box. If you are willing to buy used, you might consider a 12.5" StarMaster.

John R.

March 25, 2003 05:57 AM Forum: Equipment Talk

Who makes Nexstar OTA adapter mounts?

Posted By John Roehrig

Hi Mark,

I have Ray's brackets on my N8, primarily to allow the use of a premium refractor diagonal for 2" eyepieces. I also have their adaptor plate accessory that allows you to mount other OTAs. You will likely have to drill the bracket yourself to accept your mounting rings. I have used the adaptor plate to mount my Televue 85mm refractor using the TV clamshell.

You may have a couple of problems, depending on your scope. The adaptor plate is 2.5" wide. If the mounting screw spacing on your mounting rings is greater that 2.5", they won't fit the bracket. Second, the TV 85mm does not reach zenith because it is too long. This is likely due to the "straight up" position of the N8 mount arm. The smaller Nexstar mounts, referred to previously in another reply, are curved so that the OTA can reach higher in the sky. I have also tried the N114 mount and Baader bracket with a Pronto and had difficulty getting it to balance when using 2" eyepieces. Others have had more success with this configuration.

John

April 24, 2003 07:45 PM Forum: Equipment Talk

Broadband nebular filters?

Posted By John Roehrig

Hi James,

I think the general impression is that the broadband filters are not selective enough, the OIII filters are too selective (but useful under some circumstances), and the narrowband filters are the best compromise and most useful. I have Orion broadband and Meade narrowband SCT filters as well as Lumicon UHC and OIII filters. My general impression of them all agrees with what I said above - the narrowband or UHC filters are most used.

John