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First "real scope" recommendations and ideas


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#21 Planetech

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Posted 09 May 2016 - 05:45 AM

OK thanks.

I am thinking of ordering one of the 4000 eye pieces to try on the planets. I'm hoping that it will clear up the fuzziness I'm seeing. I did go through the collimating procedure in the book and found both mirrors slightly out. After "tweeking" them I did notice a slight improvement but they were very close right out of the box.

One thing the book doesn't get into much (and for now doesn't bother me) is the definition setting circle can not be moved and appears to be set to align with that axis but the RA setting circle can be rotated if that axis is loose. What puzzles me is the circle and pointer both move together when using the fine adjustment cable. Makes no sense to me. Seems the circle should stay put once set .

#22 Planetech

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Posted 10 May 2016 - 01:30 AM

Declination , not definition !!!!! COMPUTERS!!

#23 MistrBadgr

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Posted 11 May 2016 - 02:48 PM

The R/A scale has to move so that you can set it, based on the RA of the object you point the scope at.  The declination scale is fixed to the mount and a needle moves around to give an indication of degrees the scope is pointing from the polar axis.  The polar axis is fixed, so the scale is fixed.  RA position will change with the position of the object, so you have to be able to reset it.

 

Hope this helps,

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#24 Planetech

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Posted 11 May 2016 - 06:04 PM

After I sent the question I got to thinking about it and thought that was the case. Thanks for confirming it. BTW I ordered a 9.7 mm 4000 and should have it Monday. I'm interested in comparing it to the 9mm that came with the scope. Hopefully it will reduce the color "aberrations" if that's what you call it.

#25 MistrBadgr

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Posted 12 May 2016 - 04:59 PM

You will see a wider field of view and it should handle the differences in color refraction better.  Mostly it will be better in the outer part of the field.


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#26 Planetech

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Posted 14 May 2016 - 05:33 AM

Looks like the weather won't be decent here is Missouri for several days but that seems to be the case when something new arrives.

I did shorts one of the cables by about half and the other one (RA) will be shortened to about an inch. I find that the longer they are, the longer it takes to damp out and they really are longer than I like.

I cut through them with a deemed tool with cut-off wheel, stripped back the plastic sheath, cleaned out the old glue and re-set the cable into the knob with 5 minute epoxy. Worked great.

#27 MistrBadgr

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Posted 14 May 2016 - 11:23 AM

Yep!  That works!

 

To cut out some more wiggle, you can put some weight where the tripod brace attaches to each leg to give it some more inertia.  What worked even better for me was to make a relatively heavy eyepiece tray out of a couple pieces of 3/4 inch plywood glued together.  I was able to cut about a dozen 1 1/4" eyepiece holes in a circle of the wood.  I then cut another piece of the 3/4" plywood to fit inside the original eyepiece tray and put a pin in the middle made out of a quarter inch bolt and drilled a hole in the middle of the new tray.  Put something slick between the two pieces of plywood and you have a nice Lazy Susan eyepiece tray.  The rotational inertia of the tray really decreased the vibration time.

 

I then made some vibration pads to go under the feet of the tripod legs.  I used three pieces cut off the end of a one by four, then cut a bunch of squares out of a mouse mat ( about half the thickness of an old style mouse pad)  With experimentation, I found that four or five layers is optimum.  Five layers is a little bit much and acts like shock absorbers that are going soft, but not bad enough to change.  I used five, but if I made another set, I would use four.  I put a ring of silicone window caulk around the underside edge of each piece and glued the stack together on top of the wood.  I pressed the pieces down, but with no caulk in the middle, it made a bit of a cup for the tip of the tripod leg to fit into.

 

The next step was to build a light hood (most astronomers call this a dew shield, but that was not my purpose).  I cut the bottom out of a metal, unused one gallon paint can.  I painted the whole thing with a flat black Rustoeum spray primer.  This is the flattest, blackest material I have found.  I happened to have some light trap material that I lined the inside with, but I don't think that is as necessary as the flat black paint.  The original lid end of the can is what I taped to the open end of the scope to form a bit of a light baffle to shield the inside edge of the telescope end.  The little folded/crimped edge of the can does not fit exactly on the scope, so I glued on a few bits of Popsicle sticks (painted black) around the edge of the old can edge that the lid fit into, to give me a more stable contact.  A number of bands of black plastic electrical tape finished the job.  The contraption works really well, plus I found that it improved vibration dampening a little bit.

 

The whole thing makes a pretty snazzy little scope.

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#28 Planetech

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Posted 14 May 2016 - 05:50 PM

Sounds like some good mods. I don't have much need for the can as we are usually at state or national parks out in the boonies. I will use some of the anti vibration ideas though.

#29 Planetech

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Posted 26 May 2016 - 04:46 AM

It looks like I should invest in a Cheshire to collimate the 130eq. I can't seem to get it to give me a real crisp image of Jupiter with the 9mm eyepiece. The bands are visible but just. Mars is low and there is a lot of atmosphere to look through so that may be part of the Mars "fuzzies" and Saturn is also not as sharp as I've seen with lesser scopes.

On the bright side. The other night while dialing in Jupiter with the 26mm eyepiece, I experienced a satellite zipping past. That was pretty cool.



#30 MistrBadgr

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Posted 26 May 2016 - 02:56 PM

Getting that last bit of collimation on a short focus reflector is really important.  They are not as good as refractors for planetary and double star work, but they can get the job done if the collimation is really "on."

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#31 Planetech

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Posted 31 May 2016 - 06:43 AM

Traveling now about every 2-3 days, I couldn't order a cheshire.  I found a site on S&T or Cloudy Nights that showed how to make a tool with a 35mm canister.  I happened to have one in my camera bag and if I did things correctly, found both mirrors were off a bit.  Of course, since I did that, we've had no good weather. 



#32 MistrBadgr

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Posted 31 May 2016 - 01:21 PM

Telescopes, when you get them ready to try out, are the best cloud magnets anywhere. :)

 

Bill Steen


Bill Steen, Sky Hunters' Haven Observatory, Broken Arrow, Oklahoma

#33 Planetech

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Posted 21 July 2016 - 12:55 PM

Bill,

OK, it's been a couple of months and I ordered and received a laser and cheshire.  After a bit of a learning curve, I believe I have this scope dialed in about as close as I can get it.  The laser and cheshire agree and the star test looks good as well.  I'm getting the impression that once we get below about 9mm with the eye pieces, the definition starts to go away.  The 6mm that came with it must be pushing the limits. Saturn looks pretty clear down to the 9mm..  (my old eyes might have something to do with it as well.).  

 

Can you see the Cassini ring for example? 

 

I can make out the color bands on Jupiter and 4 moons but not the red "dot". 

 

Your thoughts,

 

Tony






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