Posts Made By: Louis Busby

May 27, 2012 12:50 PM Forum: Takahashi

Collimating a Mewlon

Posted By Louis Busby

Hey Hans,

Easy? Indeed not. Suffice it to say that collimating a Mewlon can be a challenge. However, the best source is calling TNR and talking to Fred.

After facing a similar endeavor, I too called upon Fred's expertise. I'll paraphrase most of the discussion:

Collimate in the daylight -- Place the OTA on a bench at sufficient height so that you can look into the OTA from the front at eyelevel.

Cut a piece of cardstock 12X12 inches square and then cut a 3/4 to 1 inch hole in the center. Use the card by holding it up to your eye, move it back and forth or adjust your viewing distance from the OTA so that the card blocks most of what you can see and the center hole shows only the OTA opening. This allows you to align your eye more or less to the OTA optical axis.

Holding the card in place as described, you will see the secondary shadow more or less on the primary mirror and two sets of secondary spider vanes. One set is the actual spider vanes and the other set is the reflection of the spider vanes in the primary mirror. Note the position of the of the two sets of secondary spider vanes. In a perfectly collimated scope, the two sets of vanes will be perfectly aligned over top of one another appearing as a single set and the shadow of the secondary will be centered in the concentrical reflection of the primary giving a kind of donut appearance. This is your objective for collimation

If the OTA axis is misaligned/out of collimation, the spider vanes will not appear as a single set and the secondary shadow will not be centered in the primary mirror's reflection. Adjustment is required at this point using the three sets of correcting screws each paired with a push/pull screw at the back of the secondary mirror. Please use the attached, rather crude drawing provided by Fred of TNR. In two following posts I provide Takahashi's collimating instructions.

Once adjustments are made in the daylight, very close collimation is achieved sufficient for most applications including astrophotography. More precise collimation can be achieved using an artificial star or Polaris. These being relatively fixed points of light. Usually, you don't have to resort to this level of adjustments.




July 22, 2012 11:15 AM Forum: Home Observatories

Solar Power

Posted By Louis Busby

Thanks everyone for the input. Based on the cost of such an endeavor, I've decided to go with shore power. An electrician was out yesterday to discuss my requirements and I expect a quote tomorrow.

I'm looking now at running electrical 200 feet from my house to the observatory, adding three "in observatory" dual receptacle outlets and one external weather protected dual receptacle. All on a separate GFPI circuit.

Aside from the equipment I've already enumerated, I intend on either running a small electric fan or getting one of those small room portable air conditioner/de-humidifiers. I'm thinking a small fan would keep air moving on cool humid nights to reduce or eliminate dew issues. The AC/De-humidifier would be used for limited environmental control inside the observatory when its sealed up during the day. Any thoughts on these accessories.

Also, what really should my concern be regarding lightening strikes/grounding of my system? I live in N. VA and I get some pretty good late afternoon T-storms through here in the summer months.

The climate/sky condition here is generally excellent in the fall, winter, and very early spring. Cold in the winter, down to about 32 and occassionally lower, but generally in the range of 35-45 daytime and 32 down to 15 night time. Nightime observing is really excellent. Summers are hot, hazy and very humid. My observatory is located on open old pastureland near a 2 acre pond. Dew is a serious problem for unprotected equipment in the open.


July 31, 2012 04:41 PM Forum: Home Observatories

August 6, 2012 03:28 PM Forum: Home Observatories

Finally got the Scope in It!!!

Posted By Louis Busby

Fully populated now and no more room for any new scopes. When it gets cloudy, I just photoshop a perfect sky.




October 2, 2012 01:54 PM Forum: CCD Imaging and Processing/Deep Sky

best DSO for 1st try

Posted By Louis Busby

M27 is a good start. Nice and bright.

October 22, 2012 06:31 PM Forum: CCD Imaging and Processing/Solar System

Jupiter: Oct 22, 2012

Posted By Louis Busby

Muy Bueno!!!

November 27, 2012 07:02 PM Forum: CCD Imaging and Processing/Deep Sky

M31

Posted By Louis Busby

Thanks for everyone's positive comments.

I too was first introduced to astrophotography through the black and white imagery of the 50s/60s. Monochrome astroimages have always appealed to me over color images largely because of the classical aspect and seemingly, the adherence to a more scientific presentation. Like fine art photography, black and white is stark and truthful. Although I enjoy looking at color astroimages, you just never really know if it's the objects true color given the nature of processing those images. Color balance is always the opinion of the image processor. I also like to underprocess a little in order to preserve realism. Too often I see astroimagers overprocessing images in order to exagerate or dramatize their images.

January 12, 2013 03:28 PM Forum: After Dark

48" Newtonian available on eBay

Posted By Louis Busby

I have just the spot for that in my backyard. Can I borrow $6M? I'll let you use the scope anytime you want.

January 12, 2013 07:41 PM Forum: Equipment Talk

WTB TMB 10 Inch APO

Posted By Louis Busby

Bill, I know exactly where you're coming from (see Pictures of Me and my Telescope). I think I am where I want to be in the hobby. I also have a Tak Mewlon 250S I can swap out when I want.

Scott

January 21, 2013 04:28 PM Forum: Politics

Another Assault Rifle/Another 5 Dead

Posted By Louis Busby

Wow, another tragedy of immense proportions. I'd guess that the kid had some huge mental issues or perhaps he was under the influence of some sort of psychotropic medication. Surely no ones really knows what drives someone to commit such a heinous crime.

I hope in the aftermath that society, or maybe the government seek ways to identify and evaluate these kids in order to identify an appropriate therapeutic approach. Maybe psychiatric evaluation, constant lifestyle monitoring and institutionalization is the answer, I don't know. Certainly the parents have a responsibility here. The longer it takes to resolve these issues with young people or anyone else that has mental issues, the greater the chance that more of these crimes will occur.