From: Mark Gaffney <markgaffney@me.com>
Date: November 7, 2009 2:01:41 PM MST
To: Astro_IIDC@yahoogroups.com
Subject: Re: [Astro_IIDC] Re: full moon...
Hi Milton,
I`m not sure how you gauge turbulence but I`ve been suspicious about my collimation since removing the corrector & mistakenly the secondary whilst cleaning a water stain from inside of the former. Maybe this is the problem? I can get the moon in quite sharp focus with the 25mm eyepiece I think but you saw my botchy Jupiter not so long ago-that was after removing the corrector etc.. When attempting to do this cleaning job I couldn`t budge the corrector so undid the screws holding the secondary (dropping it into the tube to my embarassment) in order to get my finger behind the hole in the middle of the corrector & dislodge it. I was told afterwards I could perhaps have used a popsicle stick or something to shift it! Would there be a possibility that focus looks OK visually but collimation still needs some work? Frank Mraz`s Metaguide has a collimation tool incorporated which can be used with a FW TIS camera. I`ll have to look at this in more detail. I think I`d need a steadier P.A. first but am still having trouble locating stars first for 3 star alignments. I was aligning on Markab for instance on the 5th but must have selected Scheat (which is orange in colour) instead! Orion, Canis Major & Canopus are useable later though if I coincide things right..
Mark.
On 08/11/2009, at 7:19 AM, milton_aupperle wrote:
Mark;
The image doesn't look sharp at all.
Was their turbulence or not? This is what my turbulence looks like:
http://groups.yahoo.com/group/Astro_IIDC/files/Planetary/SaturnAverageSeeing_MJA20090404.mp4
Things that affect Sharpness are
1) Poor focus
2) Turbulence
3) Poor Mount Tracking
4) Fog, clouds and Dew
5) Dirty Optics (including dirt / condensation on the CCD).
6) Not allowing the mirror / optics / Camera to cool down to ambient temperature, which also produces tube current.
Any one or combination of the above produces poor images.
HTH..
Milton Aupperle
--- In Astro_IIDC@yahoogroups.com, Mark Gaffney <markgaffney@...> wrote:
>
> Milton,
> Here it is in Files (at least Files will let me upload a Tiff file-I
> always thought things had to be converted to jpegs for Yahoo but maybe
> that`s just in Photos?)
> http://f1.grp.yahoofs.com/v1/oLX1SvSQE_EMLpGNpDgXrefKY2fhxWlXHWWJbRddjME8vnQRp8WeH3Udsnn9x6gxmheJnr9QUqODUZmCWC7E2pQ5qqQA1ktTuDgK
> I was having trouble making it much sharper than this (I did tweak the
> focus knob numerous times when doing these trying to make it finer)
> but thought conditions were quite good-there was no dew for example
> which is often a problem, even with my dew strip. I`ve hurt my back
> bringing the mount & 2 x 11lb weights inside because of the recurring
> rain periods we`re getting. I`d brought in the C9.25`s tube but if I`d
> waited to undo the screws etc. on the mount I`d have gotten soaked!
> Generally speaking the Telegizmous cover is good but I noticed some
> moisture on top of the tube after removing it after a shower the other
> day..I think getting soaked is preferable to back strain though
> somehow...!
>
> Mark.
> On 08/11/2009, at 4:38 AM, Milton Aupperle wrote:
>
> > Mark;
> >
> >
> > Why not post it to the Files section, so we can see it at full size?
> > Anything posted to Yahoos idiotic pictures section gets reduced to
> > 480x360 pixel size, which blurs it.
> >
> > As far as I can tell it doesn't look sharply focussed or you had
> > significant turbulence when it was shot, which makes achieving focus
> > difficult and capturing sharp frames difficult. Some nights here I
> > can't even bring the moon into sharp focus visually with a 25 mm
> > eyepiece at prime focus on the C8. But I live under the Jet Stream
> > and some nights I am surrounded by a loop of it on all 3 sides.
> >
> > Also, a general question to the group.
> >
> > I'm getting really fed up with Yahoo for hosting the Astro IIDC
> > group. If you've ever used the search engine here, it's absolutely
> > terrible at finding previous articles regardless of how you set up
> > the search query. Luckily I keep a copy of most of me "important"
> > FAQ type e-mails to the group so that I can flip through by date to
> > find the original posted onto the group and then refer you back to
> > the original thread.
> >
> > So I'm wondering what people think about possibly moving to another
> > group host, like Google groups for example? I have not spent any
> > time looking into the pros and cons of other hosting services yet,
> > but I will if people feel that Yahoo is just sucking too much.
> >
> > Thanks in advance for your opinion...
> >
> > Milton J. Aupperle
> >
> >
> > On 7-Nov-09, at 10:08 AM, Mark Gaffney wrote:
> >
> >> Hi, Here`s a shot taken on the 5th November (full moon) with my PGR
> >> Scorpion 1628 x1236 pixel mono camera;
> >> http://groups.yahoo.com/group/Astro_IIDC/photos/album/1179371742/pic/1436279267/view?picmode=&mode=tn&order=ordinal&start=1&count=20&dir
> >> I`m wondering am I slightly out of focus, or can the haziness be
> >> accounted for by the light of the full moon?
> >
> >
> >
> >
> >
> >
> >
>