Posts Made By: Lorne Johnson

March 15, 2011 02:56 AM Forum: Deep Sky Observing

What am I doing wrong? Can't find M31 & M51

Posted By Lorne Johnson

Okay. M31 with the 9.25 at about f 10 and 24 mm eyepiece, you are at about 95x. True field of maybe .6 degrees, or 1.o degree with an Ethos. The Great Galaxy is a good 2 degrees across, and should look better in the finder scope. You could be looking right through it.

I started out using an f15 5 inch refractor and got about .6 degrees true field maximum. I could find M31 pretty easily. The Whirlpool certainly showed up. But, everything was hard to find with .6 degrees. You have to be right on the object(and know that you're on the object.


April 24, 2011 04:00 AM Forum: Equipment Talk

mn56 collimation..how to?

Posted By Lorne Johnson

I have instructions for doing this somewhere, and will take a look for them. It's pretty much the standard newt, although I've never used a laser.

The secondary is not offset.

June 17, 2011 02:56 AM Forum: Refractors

80mm preference

Posted By Lorne Johnson

John Whitby said:

Explore scientific, Stellarvue Svr80 ED, or Orion ED80T CF?


APM f 7.5.

June 21, 2011 06:01 PM Forum: Eyepieces

maximum power eyepiece

Posted By Lorne Johnson

doug downey said:

I'm new to all this so I'm just throwing this out there.I've purchased a celestron c6 xlt which I pick up Tues.Reading reviews it says max. mag. is 354 which I imagine would be under best seeing conditions.If I want an eyepiece for such occasions should I go with something like a 3-6 nagler zoom which would be usefull from around 4mm or something I can use with a 2.5 powermate,which I have and reach max power with a another eyepiece?I realize there are other variables and I'm just curious as to other opinions. Thanks Doug

Atmospheric conditions affect seeing, and therefore, the highest useful power. This varies with location and with current conditions. Where I am 120x can often be the limit, and it rarely, very rarely, gets better than 250x.

I note that you are listed as in Whistler BC. That looks like it gets a hefty share of the Gulf Stream. So, don't be surprised if you don't get the 400x plus results that some observers do. Your environment looks more like mine.

June 23, 2011 02:05 AM Forum: Deep Sky Observing

Re: north america nebula

Posted By Lorne Johnson

It's quite easy to look right through the NA Nebula. It's good to have at least a 1.5 degree true field of view.

July 3, 2011 02:33 PM Forum: Equipment Talk

telescope and mount options

Posted By Lorne Johnson

I am only replying because no one else has (imaging is too expensive and all-night for me). You can get results with each of those systems, and each will have its strengths and weaknesses. The difference in portability and set up between the 80 mm triplet and the SCT its pretty substantial depending on how many feet you actually have to carry the thing. For imaging, you want to know what each will do better and why. The mount is the hard part for this (especially the tripod, pier, or permanent pier).

I would recommend finding a local club and working with, or visiting with folks who do this. The experience will save you a lot of money, frustration, and probably time. It's good way to find out what the issues really are, and how far in you want to get. It's all a set of compromises.

I do own an 80 mm triplet and a Vixen GP mount with a massive surveyor's tripod. I got the scope for a quick look, spotting, and in case I got the imaging bug, and stuck to the 80 because I already had the mount. It's a superb 3 inch, but for visual, my 8 inch dob just kills it, more than twice the resolving power (planetary) and 7 times the light gathering power (deep sky).

July 11, 2011 02:55 PM Forum: Eyepieces

nagler 13mm

Posted By Lorne Johnson

I'm pretty sure the 13 Naglers were only made in Type 1 and Type 6.
The Type 1's have a 2 inch barrel with a 1.25 barrel inside it.

The Type 6's have a 1.25 inch barrel, and will fit in my pocket (not that I would actually put it in my pocket under ordinary circumstances).

August 10, 2011 04:54 PM Forum: Beginning Astronomy?

Cooling the primary mirror

Posted By Lorne Johnson

You'll see a wavering image, same idea as the wavering above the surface of a hot road (but hopefully not that bad).

Of course atmospheric turbulence produces the same effect (or at least a very similar one). Both are made worse by higher power.

You can see a lot without a fan, although they get more important with larger mirrors. What happens is that when we get more experienced we start looking for our best-view-ever of objects. That pushes us to seek out the last few percentage points in a world of diminishing returns. In other words, at some point you'll know that you think you need a fan (maybe four fans).

November 5, 2011 01:54 AM Forum: Eyepieces

2x Televue Barlow question

Posted By Lorne Johnson

Paul Maxson said:

Hi all,

Does anyone know if you can increase the 2x 1.25" Televue's amplification with extension tubes? I'm not talking about the Powermate, just the 2x barlow.

Thanks!!
Paul

I believe that you can increase its magnification by putting the barlow ahead of the diagonal (extension tubes should do the same thing in a newtonian.

May 7, 2012 01:57 PM Forum: Equipment Talk

Collimation of Intes MN56

Posted By Lorne Johnson

It will take 24 hours for me to find it, but I have good instructions. ITE telescopes wrote them, and would probably help you out.

(My biggest challenge was getting the focuser square on the tube.