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Posts Made By: Rod Mollise

January 12, 2008 03:18 PM Forum: Equipment Talk

Coating scratches in refractor... effect on images

Posted By Rod Mollise
James Sarte said:


Now, I received an achromatic refractor which had some sort of residue all over the primary. Instead of sending it back again, I decided to just clean it myself. I suppose due to my frustration, I didn't take the time to clean it carefully, and as such managed to put a few very light scratches in the coating. Of course, these scratches are only noticeable when shining a flash light down the tube.

Thanks!

Maybe you scratched it.
Maybe you didn't.
Maybe there aren't any scratches.

The "flashlight test," which is what you have done, is a sure way to make any lens or mirror look HORRIBLE. Don't do it. Don't worry. And don't take anything apart again. If you put scratches in the coating (which I doubt unless you use a piece of sandpaper for a cleaning tissue), they will have zero effect on images. Just get outside and enjoy your wondeful telescope; no obsessing allowed!

8)


January 15, 2008 07:47 PM Forum: Equipment Talk

UV/Skylight filters

Posted By Rod Mollise
Larry Seguin said:

Read about these filters, thought I might get one for my 17 Nagler, to protect that honking lump o' glass on the bottom. Question is: is it worth bothering? It doesn't sound like it would lose much light, but it seems to be simple optical glass, and I wonder about the effect on the image quality. Any thoughts?

Yes...forget about 'em. Many of these filters are poor optically and all are unneeded if you treat your eyepiece with reasonable care.

wink

January 16, 2008 03:00 PM Forum: Equipment Talk

LXD75 and the LX200 protocol

Posted By Rod Mollise
Rob MacMorranam said:

Can anyone tell me if Meade's LXD75 mount 'speaks' the lx200 protocol? I'm trying to figure out whether I should be considering it as I decide which telescope to buy. I want to be able to interface it to Starry Night or TheSky, which both support Meade's lx200 protocol, but I can't seem to find a definitive answer on whether the LXD75 supports it. Perhaps it requires AutoStar?

Thanks

Yes.


January 17, 2008 01:36 PM Forum: Equipment Talk

CG-5 and C11 - ok for short exposures?

Posted By Rod Mollise
John Miele said:

What are the chances that a C11 mounted on a new CG-5 mount will be able to take unguided 56 second images without trailing? I know that this is quite a load for the mount. But I will be using anti-vibe pads and will be careful to balance well. Nothing piggybacked on the scope. I will have a 9x50 finder mounted and I’m using a Mallincam video camera. I would be happy to get un-trailed images maybe 75% of the time with such a setup. Any chance of getting that performance? I can only integrate up to 56 sec with this camera so I don’t need to go longer. If I want to expose longer in the future I will upgrade to a beefier mount for sure. Just curious as to what I could expect with the CG-5. Thanks.

John

"Slim to none." I have been able to do decent 30 second unguided images (not all frames perfect) with this mount and a C8. OTOH, I can autoguide it for as long as needed, and have done 20-minute guided exposures with the C8 at f/4 regularly with good results.

The C11 will make things tougher because of its longer focal length and because it will be even more prone to shaking if the wind comes up--that has spoiled more than one imaging session with this mount for me despite the fact I was using a Stellacam II and a C8, which meant shorter exposures and less focal length. You'll also be dealing with a small chip, which will make things even harder vis-a-vis trailing.

Bottom line? Very good as a low cost imaging platform with a C8...C11? Not so much. If you want better, and really want most frames perfect, the place to start would be the Atlas (EQ6) mount and work your way up from there. You'll also want to get your focal length _down_ with a 3.3 reducer.

January 17, 2008 01:46 PM Forum: Refractors

Celestron Omni XLT 120

Posted By Rod Mollise
James Sarte said:

On a more serious note, there appears to be something like tiny metal flakes or specks sandwhiched between the doublet pair. It could be dust. I'm thinking metal specks because they look shiny when focusing a flash light on them. There's also a very light .75 - 1" coating scratch on the secondary doublet inside the tube. Can't really see it unless looking at an angle. The lens facing outward is clear, and coating is uniform.

None of these things will harm your scope's performance. You are doing a variation on the good, old "Flashlight Test," which will make any optical element look horrible. The Omni XLTs are nice scopes--especially for the price--get out and enjoy yours.

8)

January 18, 2008 02:22 PM Forum: Equipment Talk

W.O. doublet or meade triplet?

Posted By Rod Mollise
Andrew Box said:

Hey everyone,

I've read good and ok things about the new 5000 series 80mm meade apo triplet, and also about the William Optics 80mm doublet ED scope. Some say the meade is quite excellent, especially for the money. Some say the W.O. ED is 'just' a semi-apo, but of fantastic build quality and good optics. I just want to get some nice high-contrast wider fields of view than the f/10 SCT can offer and probably will also do some imaging with a digital SLR.

I haven't had a chance to try one of Meade's scopes...but I will say that I have been incredibly pleased with WO's gear, particularly their ED refractors...and their support. I simply do not think you can do any better in this price range.

January 18, 2008 02:26 PM Forum: Celestron

Super C8 OTA and Visual Backs

Posted By Rod Mollise
Keith Proctor said:

Just purchased my first SCT recently and working on getting it set up. I don't own any 2" eyepieces yet, but if I can put a 2" visual back on this ota then I would love to invest in a few nice 2 inch EP's. Can a Celestron Super C8 support a 2" visual back? Pardon my ignorance on this matter, but just learning the ropes on sct's and finding there is a lot more I need to know.


They can... or you can just buy a 2-inch SCT style diagonal that will screw right onto the rear port. William Optics makes a niceun.

8)

January 18, 2008 02:34 PM Forum: Meade

Meade Customer Service

Posted By Rod Mollise
Ty Chamberlain said:

I called Meade today to order the washer that goes between the tube and the visual back on a LX200. Meade came back and said it was part of the diagonal and not available as a part! So I have to buy a diagonal to get a washer?

Depends on what you mean by "washer." Are you talking about the threaded ring you screw onto the rear port of the scope?

8)

January 18, 2008 11:24 PM Forum: Equipment Talk

How hard to upgrade plain cg-5 to goto

Posted By Rod Mollise
Glenn Kinsley said:

How difficult is it to upgrade a cg-5 without any drives at all to the full go to configuration? Would it make more sense instead to get the standard dual axis drive and a DSC setup? I would probably be happy with just the digital setting circles, but a go to sounds so cool. I would appreciate any inputt. Glenn Kinsley

If it's a recent CG5, and you can install the Synta upgrade kit (sold by Orion...Celestron doesn't offer any means of upgrading the CG5 to go-to), not hard.

As for "should you," it depends. If you are an imager, definitely. If you want more full featured drives (more slewing speeds, etc.) than the stock dual axis kit, yeah, go for it. Frankly, the dual axis drives sold for all these mounts (the EQ4 based mounts that is) leave a lot to be desired.

If it were me, I'd sell the mount you have and buy a go-to equipped Celestron CG5.

8)

8)

January 20, 2008 03:55 PM Forum: Equipment Talk

C5 dirty optics

Posted By Rod Mollise
Charles Goodenow said:

Hi. I'm new to Astromart.
About 10 years ago I bought a used C5 spotting scope. Got a Skyview deluxe EQ mount for it. I have used it off and on over the years, my interest was never to strong. Now I have a DSLR camera and started taking pictures of the moon. In general using it more.
Dirt or dust spots show up on the photo's. I can look in thru the corrector plate and see some dust and dirt on the inside of the plate and on the mirror. Can't really see the secondary to well to tell if it is dirty but I imagine it is like the rest. Not real bad but more than just a few specks.Thanks
Charlie

Your telescope does not need to be taken apart. These dust spots are on your camera's chip. Leave poor Mr. Scope alone and enjoy him.

8)

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