Posts Made By: Jim Richberg

September 30, 2005 12:19 AM Forum: Eyepieces

Preliminary results of zoom eyepiece test

Posted By Jim Richberg

I have completed the first version of a fairly systematic head-to-head test of three zoom eyepieces-- the high end Pentax SMC 8-24mm zoom, the medium/high end Nikon 9-21mm, and the highly regarded new Apogee 7.3-22mm.

The results are somewhat complicated-- rather than try to gist them, I'll refer you to my web site if you want the gory details.
http://users.adelphia.net/~jbrspace/zoom_eyepiece_solar_review.htm

In brief, though, I can tell you that the Apogee is *not* a clone of the higher end Nikons, even if it is an OEM version of the basic Nikon "Earth and Sky" line.

Jim

September 30, 2005 12:24 AM Forum: Coronado-Lunt-DayStar Solar Filters

Test result of 3 zoom eyepieces on a PST

Posted By Jim Richberg

I have completed the first version of a fairly systematic head-to-head test of three zoom eyepieces-- the high end Pentax SMC 8-24mm zoom, the medium/high end Nikon 9-21mm, and the highly regarded new Apogee 7.3-22mm. I tested them on a "super PST"-- one of those lucky early units that appears to have ~0.6A resolution unstacked.

The results are somewhat complicated-- rather than try to gist them, I'll refer you to my web site if you want the gory details.
http://users.adelphia.net/~jbrspace/zoom_eyepiece_solar_review.htm

In brief, though, I can tell you that the Apogee is *not* a clone of the higher end Nikons, even if it is an OEM version of the basic Nikon "Earth and Sky" line. If you've got a 'standard' PST it's a strong contender, depending on your eyesight and budget. If you're running stacked PST's, I'd personally look for something higher end. 8)

Jim

December 23, 2005 12:27 AM Forum: Coronado-Lunt-DayStar Solar Filters

First Impressions of CaK PST

Posted By Jim Richberg

Today I had the chance to test out my Calcium K PST, which arrived yesterday in a box which looked as if it had been used to jack up the FedEx truck.

I've posted my first impressions at my web site:
http://www.jimrichberg.com/astronomy/Calcium%20K%20PST%20first%20impressions.htm

I know that CaK images are different and less visually stimulating than Hydrogen-alpha views, but even with this lowered expectation I find myself underwhelmed. I suspect it will grow on me with time and the use of the proper equipment (the included eyepiece is not as good as its 12mm H-a PST counterpart, IMO.) Baffling of ambient light was nice to do but not a necessity with H-a viewing, but I find it difficult to see how one could enjoy visual CaK work without doing it hooded. Oh well, I guess that's why Coronado advertises these as imaging 'scopes. :S

December 30, 2005 06:29 AM Forum: Coronado-Lunt-DayStar Solar Filters

CaK PST: second impressions/observations

Posted By Jim Richberg

Based on three additional observing sessions with the Cak PST, here some further thoughts and observations, taken from the update I've posted on my website. (www.jimrichberg.com/astronomy)

Eyepieces matter a lot with this scope! My 7-22mm Apogee zoom nearly had me convinced that the scope was defective, since I was seeing a pronounced dark circle in the central 50% of the field of view at 15mm or less focal length, much like the shadow of the secondary mirror in a reflector when an excessively low powered eyepiece is used. My Nikon 9-21 zoom didn't display this central darkening to the same degree-- though it was still noticeable-- and this eyepiece also produced a brighter image with more discernable detail. (No surprise here-- see my H-a solar zoom report Zoom eyepiece review http://www.jimrichberg.com/astronomy/zoom_eyepiece_solar_review.htm ) I tested these two zooms, the stock 20mm Kellner, a 14mm series 4000 Meade Ultrawide (which worked surprisingly well, given the number of elements inside it), a 10.5mm orthoscopic, and the Nagler 3-6mm zoom. The Nagler, Nikon, and 10.5mm ortho-- all known high light transmission eyepieces-- seemed to be the best performers, and the margin of superiority seemed greater than in Hydrogen-alpha solar viewing. (I've also heard that the Cemax Plossls are much stronger performers compared to standard Plossls in CaK light.)


Eyepieces of 15mm focal length or more seem to work the best.
Anything shorter than this gives up too much image brightness, in my opinion, and seems linked to this central shadowing issue noted above. The Nagler zoom and the 10.5mm ortho were just working with too little light to be fully effective, even when observing a part of the solar disc away from the obstructed region of the FOV. The Nikon zoom showed plage features that I couldn't spot in the Apogee zoom until I'd first found them in the Nikon, but even its' performance began to drop off below 15mm focal length settings. In this respect, the supplied 20mm K eyepiece looks like a better choice than on first blush.

The most aggressive shrouding/shielding of ambient light attainable is not overkill with this scope-- though you may end up passing out from heat exhaustion in the Summertime! sad My maximum shrouded hat with its 3-4 layers black nylon cloth was barely adequate, and I'll probably supplement it with something thicker when its time for CaK viewing. However, eyepiece fogging is already a problem with my current setup-- and this is in sub-freezing temperatures! As a "field expedient" measure, I was surprised at how well simply cupping both hands tightly around an aftermarket eyepiece cup worked. Not as good as a shrouded hat-- not by a long shot-- but it was probably two-thirds as useful in heightening contrast and bringing out features. You need a good bellows-style eyepiece cup to make this work-- the stock ones on most eyepieces are not big enough.

Practice and "time on target"-- preferably seated-- help considerably in coaxing out visual detail. This was not a surprise, since the same principles apply in nocturnal observing, but the impact seems amplified here-- probably because you start out by seeing little beyond a dim bluish orb, and work up from there. wink Several of my sessions were marked by numerous active regions in CaK light, and I could see hints of granulation as well. (Of course, if I increased the magnification to bring out the granulation, the drop in brightness killed it.) Observing from a seated position helped a lot, too. (Again, not a surprise.)

At the end of the day, the image remains dim, though. Dim enough that getting the focus exactly right could be an issue, even when using something as linear and stark as the limb of the sun. Even if you do everything you can to relax your body and maximize the contrast of the image, CaK visual observing is still a reasonably tough challenge for middle-aged eyes!

Jim 8)

January 8, 2006 04:19 AM Forum: Coronado-Lunt-DayStar Solar Filters

"Solar Tricerotops"

Posted By Jim Richberg

I've added my CaK PST to the existing piggybacked rig housing my H-a PST and 102mm Mak-Cass with Baader film. This gives me a portable three wavelength solar setup that I store fully assembled (complete with eyepieces and binoviewers attached) for quick use.

It was trivial to add the second PST to the existing CG-5 rings; the only tricky part was thinking through how to do it (the H-a scope "twists" onto a bolt; there was not enough clearance on the rings to allow the second scope to mount similarly). I ended up making a mount out of scraps of oak 1 x 3" board and securing them to the rings with wingnuts and 1/4" bolts. the CaK scope can be "screwed" onto this oak platform, which then nests on the rings.

You can see the front and back of my solar rig on the following page of my web site
http://www.jimrichberg.com/astronomy/budget_solar_trio.htm

Adding this third scope to my solar setup qualifies it for a name. (All of my favorite scopes are named... wink )
Clear skies,
Jim

May 3, 2007 01:22 AM Forum: Equipment Talk

Low Tech solution

Posted By Jim Richberg

I made a simple backboard mounted on a wooden square sized to nest atop my nearby streetlight. I raise it via a telescoping paint roller extension, which allows me to get the backboard high enough to crown the light. I obviously would NOT recommend this approach if you have any utility lines in the vicinity (ZZZAAAPPP!), but absent that complication this seems like a low tech solution that doesn't require lasing the light.

I only block the side facing me, and only erect it when I am doing fairly serious observing. No complaints from the neighbors, all of whom know about my astronomy hobby, both because I tend to do my ATM'ing in the front yard and because a 24" Dob is not a usual sidewalk sight. wink

Here is a link to the components of the setup
http://jimrichberg.com/astronomy/streetlight%20killer.jpg

Here is a picture of me putting it onto the streetlight
http://jimrichberg.com/astronomy/raising%20the%20streetlight%20killer.jpg

Clear-- and darker-- skies!

Jim

June 9, 2002 01:47 PM Forum: Equipment Talk

EQ Platforms

Posted By Jim Richberg

Richard,
Check out the following website:
http://eqplatforms.0catch.com/
This guy (Art) sells wood equatorial platforms for between $349-$500 plus shipping. They are made of unfinished wood-- you need to lightly sand and varnish it, but I understand that they are fully functional right out of the box. I exchanged numerous messages with him when I was trying to decide how to add tracking to my 16" Dob, and found him to be very accomodating-- he was willing to make me a custom-size for my 225 pound scope for no more than the standard size price. The only reason I didn't buy one was because any platform would add enough height (6+") to mess up the custom dimensions of my scope (I can see through the eyepiece at zenith flat-footed). I ended up going with a Dob Driver 2 instead, since it doesn't affect the eyepiece height and gives you "GO TO" capabilities as well, if you want to use 'em. Of the various equatorial platform options on the market, though, Art's seem to the the cheapest alternative to building one yourself. Good luck! Jim

August 27, 2002 12:01 AM Forum: Equipment Talk

12" LX200 primary scratched...HELP!

Posted By Jim Richberg

Don,
I put a nasty (2" long and 1/4" wide) scratch in the primary of my 10" LX200 when it was almost brand new. (I was comfortable enough to want to tweak it, but not comfortable enough to dismantle the OTA totally before flocking.) I feared the worst, but have been pleasantly surprised to find that the scope still is a decent performer both visually and in CCD work. As I understand it, scratches tend to reduce contrast... maybe it balances out for the contrast-enhancing effect of the black velvet flocking upgrade that led to the scratch!

I debated getting the optics replaced right after the mishap (Meade quoted me $550 including shipping), but haven't found it necessary-- even my Ronchi test results still look OK. Sure, the scope has lost a big chunk of its resale value-- but LX200 classics tanked in value when the GPS line came out anyway.

My advice is don't panic-- try the scope repeatedly before deciding to send it away or get the mirror refinished. It probably isn't worth it. I've been using my 'scope with its scratched primary for two years now, and unless I tell other observers, they even don't notice.

For my $.02 worth, you're better off saving your money and vowing never to put sharp implements in the vicinity of a primary again.

Jim


October 20, 2002 02:34 PM Forum: Equipment Talk

Adirondack Astrovid Stellacam ex Info??

Posted By Jim Richberg

David,
"Your mileage may vary" (I've always hated that weasely disclaimer!). Having heard nothing but superlative things about the Stellacam EX and seeing countless fantastic images on the Web taken by folks with modest setups from light-polluted skies, I bought one this summer. Tried it virtually every clear night for three weeks before giving up and sending it back.

It performed fine on lunar, planetary, and stellar objects--but so does my two-year old Philips webcam. The huge disappointment with my Stellacam came on deep sky objects, where it didn't capture as much detail on DSO's as I could see visually through the same 'scopes--let along two to three times more it was touted to produce on these faint fuzzies! This was through 10" and 16" scopes and with focal lengths ranging down to f/3.3

My Stellacam EX was confirmed by AVA to be functioning properly when I sent it back. "User error"? Perhaps, but this thing is pretty foolproof and I've got a fairly strong background in computers, photography, and ATM'ing. Temperature? (I was after all trying this in the worst of a muggy East Coast summer.) Well, some of the spectacular images I've seen were posted from warm climates... and I also did some testing with cold gel packs to chill the CCD sensor, without much noticeable improvement.

Perhaps I just got a lemon of a CCD, but I'd certainly recommend if you buy one that you get it from AVA. They cheerfully took mine back, and I'll certainly deal with them on my future imaging needs--gotta' support vendors that are this helpful.

If you get one, let us know how it works out!
Jim

October 25, 2002 11:46 PM Forum: CCD Imaging and Processing/Solar System

Few questions to the digi cam guys

Posted By Jim Richberg

Anthony,
I just got my CP4500 yesterday, so I'm going through the same decision process that you are. For the CP4500 here are some of the mounting options:
1. Scopetronics "DigiT" system ($60)-- works on 1.25" eyepieces with eyecups that can be removed leaving a grooved ring around the ep that is between 1.22-1.26" in dia. This includes many of the standard plossls (but unfortunately, only one or two of my lower quality eyepieces)
2. Scopetronics "DigAdapt"--can accomodate somewhat larger eyepieces like the Meade 8.8 and 14mm UWA's. I think it was comparable in price
3. Scopetronics 14 or 18mm SWA eyepieces that, when the eyecup is removed, are threaded for direct attachment to the Nikon Coolpix's 28mm filter threads. Scopetronics recommends these as producing the best image of any product they sell for the CP4500, with virtually no vignetting even at the Nikon's wide angle setting.

I understand that we're fortunate with the Coolpix line in that the zoom is internal (allowing for close coupling to the eyepiece) and the lens is small enough in diameter not to vignette under a wide range of afocal eyepieces.

As for my coupling device, I went with a fourth choice-- The Televue DRA-0028 digital camera adapter ring. This is threaded for the Nikon's 28mm ring, will fit large eyepieces like my Panoptics, and couples them as closely as the Scopetronics. It is $30 (not often that TV is the least expensive choice!) and is available from the usual sources.

BTW, if you haven't found it, I'd suggest you join the Digital Camera group on Yahoo. In under a week I've already learned an immense amount, and saved myself a slew of money as I get started. (For example, I don't know how you were planning to activate the Bulb mode on your CP4500, but it turns out that there is a cheaper alternative than either Nikon's pricey remote control or the Harbortronics unit. You can save a hundred bucks on this alone-- and that buys a fair sized flash memory card.) Good luck,
Jim