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Posts Made By: Doug Walton

March 19, 2007 06:33 AM Forum: Equipment Talk

All the buzz over the AP Mak Cass has me wondering

Posted By Doug Walton

As many of you know, a 10" AP Mak-Cass recently sold on auction here for a bunch of moola. I've lusted for one of these for years, but even before the $30K barrier was broken, they were still pretty expensive.

After seeing the AP MC-based imaging results from Alan Friedman, Roland, and others (and of course, taking into account that these folks are obviously really good at the entire business of imaging, and that it's not just the scope), it has me wondering what the high-end alternatives are.

For a Mak-Cass (with integrated cooling) in the 8"-10" range, what do people think is the next best alternative out there? I would assume a typically long FL (f/14 or longer), and my intent would be for imaging first, and then visual use second. I know TEC used to sell these, but I don't see them anymore on their website. I know that there are some Russian Mak-Cass scopes out there for sale, but I don't know their quality or consistency. Since I probably won't be finding an AP Mak-Cass that I can afford, is there a hands-down alternative to one? Would it just be better to get a high-end refractor in the 6" range and compromise on the aperture? Assume a wide range of imaging targets (planetary, lunar, and DSOs) and a high-accuracy mount (AP 900/1200, Paramount ME, etc.) and cutting-edge imaging platform that would maximize the optical performance.

I know the answer to this question isn't cut and dried, but reading your responses will be an education for me. I'm not trying to stir the pot or create a negative thread - I'm just wanted to hear what knowledgeable people think about this. The imaging bug is starting to ... bug me.


November 9, 2007 11:00 AM Forum: Telescope Making

Can you help me identify this lever thingy?

Posted By Doug Walton

Hi everyone,

I've attached an image that shows a red-handled lever on the side of a dob rocker box. I believe the way it works is like a lever "switch" - when the level is push all the way to the left, it pulls on a rod on the inside of the rocker box, and when moved all the way to the right, it pushes the rod back in the other direction. I also think it sorta locks in place at either end of its throw. It functions as an azimuth drive engage/disengage lever.

My question: what are these called, and where can I get them (or something like or, maybe better?)? It would be great if I could get one or two with some kind of adjustable-length connecting rod to go with it.


January 18, 2010 04:03 AM Forum: Equipment Talk

A-P 130 StarFire Gran Turismo Quandary

Posted By Doug Walton

Hi everyone - I'm in a bit of a quandary. I received notification that my name has come up for delivery of a new 130mm StarFire Gran Turismo - after approx. a 9-10 year wait. Unfortunately, I'm currently not in any kind of position to buy the scope anytime soon. As I see it, my options are:

1. Take delivery, and then offer the scope either for sale or auction. This would perhaps allow someone who may not have the opportunity to wait for one to get this scope. Of course, it would also allow someone with the money to step to the front of the line, so to speak, for a premium. I have no idea how I'd handle this sale/auction, or if I'd need to declare myself as an Astromart vendor or dealer for this one-time sale/auction. Up until now, I've successfully sold a lot of merchandise on Astromart (not much in the last year or two though), and all of it's been just regular selling of used equipment, almost always at an expected loss to me.

2. Offer to sell it to someone at the price A-P is gonna sell it to me.

3. Decline the chance to buy the scope from A-P, and release my place on the waiting list to someone else.

Honestly, I don't want to get into a heated discussion here about the pros/cons/realities/ethics of reselling this scope at a profit - that's something that won't yield much, because there really is no "right" answer. Mostly I wanted to post this here in hopes that someone might give me something new to think about that isn't readily apparent to me. Thanks for keeping it friendly, and I look forward to your suggestions.


April 26, 2002 01:34 PM Forum: Equipment Talk

12 inch Meade GPS for starters

Posted By Doug Walton

If he's got the money, and can lug it around, sure, tell him to go for it. Tell him to get the UHTC option as well. It should hold most of its value if he decides to sell it later. It's no more complicated than an 8" LX200 and it has a big aperture advantage, so his views will be much better for most everything. These scopes generally tend to be very good these days - if he buys from a good mail-order place like OPT or Anacortes or Astronomics then he'll likely be OK. Then tell him to get real good at collimating.


April 26, 2002 01:49 PM Forum: Deep Sky Observing

Sirius Optics planetary enhancement filters?

Posted By Doug Walton

I really can't recommend them right now. Mine (a 2" version) seems to be good at casting a greenish-gold tone over the FOV, and that's about it. I've used it under great seeing conditions, and under not-so-great conditions, and the image was ALWAYS better with no filter at all. (I'm referring to Saturn and Jupiter here). I used it on an optically excellent, collimated 12" LX200, and a 120mm Astro-Physics refractor. In both cases the unfiltered views was definitely better.


March 31, 2003 04:05 PM Forum: Equipment Talk

Equipment Review Review

Posted By Doug Walton

My suggested addition:

Astronomy Magazine (0.5/5)
Pro: They definitely are magazine copy, which plumps up the magazine, take up print space, and makes advertisers think it's maybe a good place to spend their money. Also useful for people who have no desire to read a useful review.
Con: Ridiculously lacking in any kind of useful content. A-Mag's reviews are a joke. Reviews appear to have been edited by summer marketing major interns that know nothing about astronomy, but must reduce the author's copy by 80% so that it will fit in with all of the silly photos that often are irrelevant to the article, along with the requisite image of M51 or Saturn taken in 1965. I can't think of another "review" source where the reviews routinely either make me laugh, or shake my head in horror.

March 31, 2003 04:08 PM Forum: Equipment Talk

Equipment Review Review

Posted By Doug Walton

...and Paul, I do agree that Cloudy Nights and Ed Ting's site (along with Tod Gross's reviews) are great. I've referenced these sites many, many times on my way to figuring out that Zambuto mirrors are what I like. ;-)

April 3, 2003 05:27 AM Forum: Equipment Talk

Best Collimating Tool Is...?

Posted By Doug Walton

I will occasionally use a Tectron sight tube to get the basic alignment of my dobs close to where I want it. Since my scopes are usually set up in the garage it's not really needed, but if I take them apart and transport them, then the sight tube may get used as a quick check. But I hardly ever use it once the secondary is set correctly.

I then use a 2" Kendrick laser to tweak the secondary position, and then I tweak the primary mirror so that the beam returns exactly onto itself. I do mean exactly too. That seems to be key.

Then I check with an autocollimator and tweak as needed. If I end up doing a lot of tweaking at this stage I run through the laser-autocollimator cycle again.

I've found that using a 1 1/4" Cheshire only makes things worse for me - there is enough slop when using a 1 1/4" Cheshire in a 2" to 1 1/4" adapter in the focuser that it gives me incorrect readings. So I skip that step - and I've proven to myself that I get excellent collimation without it. A 2" Cheshire is definitely superior - I believe that the Catseye guy makes them.


May 5, 2003 06:54 PM Forum: Birding Optics and Photos

initial impression, Pentax DCF SP

Posted By Doug Walton

Thanks for the report, Alan. I talked with someone at a well-known birding optics dealer the other day and asked him to compare the DCF SPs to the DCF WPs. He said that there were some features he liked better with the SPs, but that optically, they were almost identical. Just another data point until I get to look through them myself.


May 22, 2003 06:15 AM Forum: Equipment Talk