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Posts Made By: Joplin Motisher-Chittenden

April 15, 2004 11:16 PM Forum: Film Astrophotography - Imaging and Processing

Reciprocity failure and ISO

Posted By Joplin Motisher-Chittenden
The reciprocity faliure effect is more pronounced with the 400F than it is with 100F. Fuji's datasheets state that with 100F at 4 minutes you loose 1/3 stop and with 400F you loose 1 full stop of sensitivity. It's hard to say if the curve eventually results in the 100F being more sensitive. I would just do at test comparing the two films.

Joplin

April 16, 2004 08:03 PM Forum: Equipment Talk

Celestron 4" Refractor Conversion

Posted By Joplin Motisher-Chittenden
I would contact Lumicon about their 2" adapter for these scopes. There shouldn't be any modification of the scope required. Here's a link:

http://www.lumicon.com/va.htm

Item number is LVP-AD070

Joplin

April 25, 2004 11:55 PM Forum: Chinese Optics Imports

Eyepiece Upgrade Questions

Posted By Joplin Motisher-Chittenden
Scott,

I've had my 1278 since late last year and while I don't use it quite as much as some of my other scopes I have used a some premium eyepieces with it. For open clusters I like the 27 Panoptic the best, followed closely by the 19 Panoptic, depending on the size of the cluster. For globulars either a 9mm or 7mm Nagler works great. For the planets I prefer the U.O. Orthos since they really can't be beat at that price. The 30mm BW Optik 80 deg. eyepiece is a best buy for an inexpensive (less than $100) widefield and will give you 50 % more field of view than the 1.25" 40mm plossl. The edge performance on that eyepiece isn't great but even if you buy one new you won't be out more than $25.00 if you decide to sell it.

Joplin

April 26, 2004 12:47 AM Forum: Pictures of Me and My Telescope and........

Scopes please Scopes

Posted By Joplin Motisher-Chittenden
You want see some different ? Well, here's my entry. It's an 8" F8 dob built by Tony Ennis that I purchased via Astromart recently. It has first rate optics, I've gotten my best views of Jupiter this season with it. I compared it to the local science center's 8" F8 Cave newtonian last night. The Cave had the edge on tracking (it's on an EQ mount) but this one had the edge on contrast due to its better coatings and minimalist curved vane spider and small secondary.

Joplin

May 17, 2004 01:53 AM Forum: Equipment Talk

Which is more comfortable?

Posted By Joplin Motisher-Chittenden
In my experience newtonian reflectors are about the same for ease of use as refractors on an equatorial mount. Both have awkward positions which can be avoided to some extent if you plan ahead. I would consider going to a shorter pedestal/ pier mount for your 8" newtonian which probably get it low enough for the use of a chair or stool (also has the advantage that the tube won't hit the tripod). Rotating rings would make rotating the tube easier but they are heavy and expensive. I wouldn't trade it in for a 120mm achromat refractor though. A Refractor in that price range is useful but an 8" newtonian will outperform it on most objects. I based by conclusion on the 8" F4 , 8" F8 newtonians and a 5" F8 refractor I currently own.

Joplin

May 23, 2004 04:25 PM Forum: Equipment Talk

Easy mounting plate for LX90

Posted By Joplin Motisher-Chittenden
Is this what you were looking for ?

http://www.petersonengineering.com/SkyDiv/m_a_ii.htm

Joplin

June 4, 2004 03:23 AM Forum: Equipment Talk

Premium 8" reflector or Celestron 9.25" XLT?

Posted By Joplin Motisher-Chittenden
Though I haven't as yet compared them side by side I have an 8" f8 dob with a superb mirror and a C9.25 (starbright coatings) that I use frequently. Which is better depends on what you are viewing/ viewing habits and observing conditions. The 8" aclimates to the ambient temperature much faster so it's better for quick looks. My 8" offers a nicer view of the planets on an average night but the difference lessens once the C9.25 has stabilized on a steady night. The dob also much more resistant to dew if you observe in humid conditions (a dew heater may be necessary for the C9.25 if the humidty is really high). The C9.25 is easier to view through if you like to observe seated but wouldn't have much advantage if the dob were shorter (like f5 or f6) or setup on a GEM with rotatling rings. The C9.25 offers better views of deep sky objects as long as you can fit them in the narrower field of view. Photography with the C9.25 is easier. The C9.25 is an excellent all around scope but it can't quite match the views through a newtonian with really well figured set of optics.

Joplin

June 7, 2004 02:38 PM Forum: Star Parties

Question

Posted By Joplin Motisher-Chittenden
There is this one midway between Fayetteville and Fort Smith, AR
Hopefully this long link will work:

http://SkyandTelescope.com/resources/calendar/?pos=1&state=AR&country=1&cal_date=2004-00-01&cal_date_month=00&cal_date_year=2004&txt=&go.x=25&go.y=13

Joplin

June 10, 2004 10:27 PM Forum: Birding Optics and Photos

remote release

Posted By Joplin Motisher-Chittenden
Here's a link to the company that makes the Shutter-Beam, an infrared beam trigger system:

http://www.woodselec.com/

Joplin

June 17, 2004 12:36 AM Forum: Film Astrophotography - Imaging and Processing

Aging films

Posted By Joplin Motisher-Chittenden
I've found the modern fuji negative emulsions to be very stable. The film base will be different from your older negatives, which may be part of the difference in color balance. In general, the orange film base color fades over time so with older negatives it is actually easier to remove the color cast left by the orange film base. It might help if you could post an image of one of these negatives scanned as a slide rather than a color negative.

Joplin

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