Posts Made By: Gianluca Valentini

Hello everybody,

is there anyone out there who can suggest where I can find hints on building a pier to mount the 11 GPS on its fork mount in equatorial mode, but without using a wedge, if at all possible. I've been told and I read that the wedge introduces a lot of unnecessary vibrations.
Thanks for any info anybody will be able to provide.

Ciao
Luca

Hello Norman,

read he last issue of Sky&Telescope: there is a very interesting article by a participant of this forum (thanks Johannes) on DSLR astrophotography. There you'll find the info you requested.

Hope it helps
Ciao
Luca

Hello everybody,
before posting here a question about equipment I checked the equipment and refractor sections, but I could not find any useful info. Furthermore, my question is only partially out of topic, as it refers to the photographic qualities of the instruments mentioned.

My question is substantially this: is there anybody out there that has experience with both these scopes as traveling/imaging tools? I know it is highly unlikely, but it was worth a try! It would be very helpful if a WO owner could give me his impressions on the 80mm scope (the F6 fluorite version)

Is a fluorite triplet design always preferable to the classic Tak doublet for color correction?

Thanks for any help.

Ciao
Luca

Hello guys,

I hope somebody can answer this: I've been trying to perform a drift alignment and I thought I got it although the altitude alignment (the one close to the eastern horizon) was not perfect (clouds rolled in) since the star showed a small drift in the 5 min. tracking at 225X (a little more than half radius drift). I remembered that the "5 minute" rule was to keep the star without any N-S drift for at leat 5 minutes to achieve exposure times in the order of the 2,5 hrs. without any field rotation.
However, I assumed that I did not need that long and so I was content of the little drift registered.

I assumed also that that, once well aligned, my scope would have tracked any star in the sky keeping it in the center of the eyepiece even at 225X for a long period of time (with small errors due to the intrinsic mount ability to track).

My problem is that, when I do this and center a star, this seems to move slowly but noticeably to the east (always at 225X): CAN ANYBODY TELL ME WHAT THIS MEANS IN TERM OF ALIGNMENT?
Is it a consequence of the fact that I did not have a 5 minute alignment on the altitude adjustment? The movement was very very small though and for the most part of the 5 minutes almost undetectable. I'm confused.

Sorry for the long post but I didn't know how to put it in a shorter way.

Thanks for any help.

Ciao
Luca

Hello everyone,

is there anyone kind enough to suggest a cleaning method for an 11" corrector plate? Would water and a mild soap work? Or is it better to just use a high quality microfiber?

Thanks for any help.

Gianluca

Well guys,

I finally was able to take my first CCD shot. It seems like the way will be steep and long! I also had to go through the experience of taking flat fields, since I imaged at F3.3 and all shots had a very noticeable vignetting.
Focusing has been a nightmare, as predicted. I tried to apply some tape to provide diffraction spikes, but they were nowhere to be seen! (how wide should an obstruction be to create proper diffraction spikes?). I am astigmatic so I need an objective tool to judge focus and the brightest pixel offered by CCDOps is not enough.
I also had some problems guiding (my 1st experience) since I could not find a proper guide star. So I had to go unguided and my mount had a hard time tracking at F3.3 for 30 seconds even though my polar alignement is very very good!! So it has not been an easy one for me.
So the attached picture is a crop of the image I took and reduced with a t-shirt flat (alas, not so good, but I have another 4 sets to try out with diffeent average saturation levels). It is 50% the original size (1600x1200) and cropped.


On top of all this I know very little about processing.

Nexstar 11 on APT wedge
.33 FF/FR
SBIG ST-2000 XCM+IDAS LPS
20 5" shots averaged to which I added 10 averaged 30" shots (adding or averaging? I never know which to use!). So it is only a 6 min. exposure.
The ST-2000 XCM "one shot color processing" applies a DDP to the single color channels and I must admit I am not crazy about it (very noticeable dark haloes around stars)but the simple RGB processing provided with the camera software is not great either. I applied only a very light unsh. mask.

Help and advice would be greatly appreciated, as usual.

Ciao
Luca

Hello everyone,

is there anybody out there that can suggest any of these two products. They cost approx. the same (The Optec is actually cheaper at the source, but importing it in Italy, would come up at about the same price). The Baader Allen Gee II provides a variable reduction ratio (.35 to .59) whereas the Optec MaxGen is only .5.

That's all the info I have: can anybody add something useful for the choice?

Ciao and thanks to anyone who'll take the time to reply.

Cieli sereni (clear skies in Italian)

Luca

Hello guys,

I know that the attached image is out of critical focus, but I would like to know also about all the other problems that I'm sure will jump to the eyes of experienced imagers such as most of you guys out there. I am at the beginning of both imaging and processing so I need all the advice I can get! This is in fact only my second image and, since the moon was up, M42 was the only target I could think of. 8)

Equipment:
NS 11" on APT wedge (permanent on pier)
Approx 53 min exposure (the project was 4 15 min. shots, but the last one was aborted for loss of guide star as some clouds must have passed in fromt of it) with ST2000 XCM (one shot colour) at -25°.
Images aligned and reduced (dark frames) in Astroart; 1st experience with levels and curves in Photoshop CS and a little R-L deconv. in Astroart.
Image size reduced 50%.

Thanks and cieli sereni to all.

Luca

Hello everyone,

in a recent post about a processing problem, Larry Durst posted this link: http://www.lefevre.darkhorizons.org/articles/proctutorial2.htm
I checked it out and it seemed very good, but when I tried to print it, I could not access any of the chapters from the 5th onwards. I tried to contact the website via email but without success.

Does anyone have the remaining chapters saved somewhere on HDD?
Is anyone else able to access those chapters?

Thanks for any help you'll be able to provide.

Ciao
Luca

Welcome Kirk: that's what I would call an entrance in style my friend!

Great picture, nice colors and detail. I apologize for my ignorance, but I don't know which FL you were filming at, since I don't know the 152ED scope you mention.

Thanks for posting and keep doing it.

Ciao
Luca