Posts Made By: Leif Edmondson

If one were looking into buying an 8" to 10" SCT for amature level astrophotograghy, what is better, an Alt-Az mount or GEM? Both have plenty of goto, auto tracking capabilities from the major mfr's. But does one have a clear qualitative advantage over the other?

How come emission nebula typically look red in photos but grey or a little green or a little blue in the eyepeice? It can't just be a filter on the camera because all the stars in the photo are typical star colors.

I'm just getting started with film based astrophotography. My guided scope mount is not highly regarded for astrophotography but I'm going to see what I can do with it. So at this point I am most interested in wide angle, whole constelation shots and secondary interest in brighter DSO's, moon and planet subjects. I own an old manual Nikon 35mm camera and want to know what kind of film to buy. Many years ago I bought a roll of B/W ilford film for some shots of the moon and recently I've just been using off the shelf 400 speed color print film. And I have to rely on my local camera shop to develop all my film (and they've done well with the two rolls I've given them). I'd appreciate opions and recommendations on films that would do well for my gear and interests. Is slide film better? Is B/W better? What works well?

I have just finished construction of my mirror box of my 16" F5.5 truss scope, actually all of the mechanical parts are done (yeah!). Its now time to start "finishing" it. Any one care to share how to spray paint the inside of the mirror box black, without getting any paint on the beautiful baltic birch exterior? I'm thinking of masking tape (painters grade). But for great results do you attach it to the inside surfaces or the actual edge of the box? I'd really appreciate getting some tribal knowledge on this.

I am finally ready to install my 16" mirror into its new mirror box. I built it right along the lines of Krieg/Barry dob book. Is it better/safer to install the mirror into the cell and then put that assembly into the mirror box? Or is it better to install the cell into the box and then insert the mirror? does it matter? I'd really appreciate some input from those with some experience.

I am finally ready to install my 16" mirror into its new mirror box. I built it right along the lines of Krieg/Barry dob book. Is it better/safer to install the mirror into the cell and then put that assembly into the mirror box? Or is it better to install the cell into the box and then insert the mirror? does it matter? I'd really appreciate some input from those with some experience doing this.

My Celestron ASGT mount arrived yesterday and after a quick read through the manual I have a question I'm unable to answer yet and I'm hoping one of you will know.
Can the mount be pointed manually at an object, then tighten the clutches and track at sidearal rate, or does it have to go through one of the alignment routines? I wouldn't expect goto to work like this but I'm just curious if it will track once I point it.
Thanks

I just got my tracking mount working and I'm hoping someone on this forum can provide me w/ a formula.
How do you calculate your optical systems "prime focus" magnification and field of view. I've got a 120mm F5 (600mm) refractor and a NIkon 35mm camera. So I want to shoot some basic shots of some deep sky objects but I'd like to know what will (and wont) fit before I waste time and film.

Thank You,
Leif Edmondson
Boise Idaho

Hello Dan

To view M51 be patient. Despite all the photos you have seen of a majestic pair of galaxies in deep space - IGNORE THEM. This object is FAINT, and SMALL. I have a 10" f6 hand guided dob that I have acquired M51 with for the first time earlier this year. It was tough going.

Use a star chart and your finder to get in the right vicinity of the sky (Don't expect to see m51 in your finder). Use your biggest eyepiece (EP). Since you say you're a beginner, I'll guess you've got a 25mm and a 9 or 10mm, stick with your 25. Scan the sky slowly and patiently. You are looking for a pair of FAINT, Smudgy, fuzzy SMALL spots fairly close together. Once you get your scope close to the right location, stare into the EP and look for the fuzzies, move your concentration around the EP view for a couple of minutes and just ask yourself 'could that be it’. Bring your eye to focus on what you think it might be and consider it for a moment or two, you'll be pretty certain when you've got it. It will look like a pair of smudgy white spots. Only when you’re fairly certain that you’ve got it should you switch up to a higher power EP. If you’ve got an 18mm EP I’d bet you’ll get fairly good detail in a 10”f10 scope. If you use a smaller EP (much higher power) than that, it might be ‘too close’, don’t know I’ve not used a 10”f10.

You may not see the arms at all with your scope. I just looked at M51 through an 18” last weekend and didn’t see the arms connecting the two galaxies at all, although I saw a LOT more detail in the larger galaxy with the 18” scope than I’ve ever seen with my 10”.
It took me about 8 tries to find M51 and I was somewhat underwhelmed when I finally knew I had it. The pictures I’ve seen of this object over sold it to me quite badly. Although I will say that as I look at it more, the more detail I learn to make out.

As for determining the visible magnitude of your skies try the following. Get a good star chart – down to at least 6th magnitude – really, buy one that goes all the way down to at least 8th mag. Go out and look at the little dipper – can you see ALL the stars of that constellation from your back yard? If you can you’ve got about 4.5mag skies – really pretty good for a back yard. Can you see fainter stars? BONUS!
I found M51 in mag 3.5 to 4 skies from my back yard.

Also I’d advise trying star cluster objects first, they are easier to locate and more immediately satisfying than galaxies at first. They will help you learn your eye skills and your star chart reading skills with a little quicker pay off. I find galaxies are usually tough to find and somewhat of a let down when I compare what I see through the EP and what I see in Astronomy or Sky and Telescope magazines. Take your time, be patient and keep trying.

Clear Skys
Leif Edmondson

One of the other guys at the event tried for that earlier in the evening, while it was still lower on the horizon and somewhat behind a tree and it wasn't worth bothering with at the time so he moved on. He also tried for the trifid and it wasn't very good that close to the horizon. but summer is coming soon, it was definitely a taste of things to come!