April Fool's Night

I obtained a tripod mounting block for use with mounting rings and used it to mount the 80ED refractor (with 2" diagonal and 19mm eyepiece, 31x) on the Paragon-Plus XHD tripod. The scope still is out of balance, but a bit less than before, making this combination a little more comfortable to use. This time I also attached the Rigel QuikFinder.

From my light polluted patio, I observed M97 with the refractor. I could only detect it by using the UHC filter. It looked like a featureless roundish smudge of a few arcminutes across near a triangle of stars. M97 forms a right triangle with two if these stars.

Globular Cluster M3 was easy to find. It is visible as round nebulosity that gets dimmer towards the edge. In the same view, two bright magnitude 6 and 7 stars are visible, and M3 itself sits in the "center of mass" of three other stars (mag 8.4, 9.8 and 10.6). M3 is about 3' across in the refractor. No stars of M3 itself were resolved. I am rather surprised that even though I am observing from my patio and high clouds are sometimes reducing the visibility, the limiting magnitude at this magnification is about 11 (towards the east, at about 50 degrees altitude).

At 22:30 I observed Saturn in the Western sky. Its moons Titan (mag 8.4) and Rhea (mag 9.8) were easily visible. I did not detect any other moons. Besides the rings, Saturn did not show any details. At 31x I could not detect the cassini division (which is not surprising with such a low magnification). The effects of atmospheric diffraction were visible when Saturn was slightly out of focus.

I also observed Castor. I could not resolve this double stars (mag 1.9 and 2.9 separated 2.5") at this magnification. I could easily see the mag 9.8 star 72" away and a mag 10.4 star 3' away.

Double star nu-Draconis was an easy target as well. These mag 4.9 stars are 62" separated. They appear white. I was confused for a moment, thinking I was looking at the wrong object, but then I realized magnitude 6.5 GSC 3893:353 is a non-existent object. After realizing that, the star field made sense (field of view is 2 degrees across with this configuration).

At 00:25 I also observed Albireo while it was rising above the East horizon. Even though it was only 10 degrees above the horizon, the orange and blue components were easily separated (34"). This double star is always a joy to observe.

Finally, I observed Jupiter and four of its brightest moons in the Soutern sky. Two cloudbands of Jupiter were obvious, but no other details on Jupiter were observed. Again I noticed the effects of atmospheric diffraction on Jupiter, which surprised me at 50 degrees altidude. I didn't notice color fringe, but had trouble focussing Jupiter. It more looked like a focus problem of my own eyes than bad seeing. I wonder if the Panoptic is to blame.

Polaris and the Ring Nebula

This evening I mounted the 80ED refractor on a Paragon-Plus XHD tripod. Attaching the 2" diagonal and 19mm eyepiece result in a tail-heavy combination that is too much out of balance for comfortable use. I need to get a tripod mounting block for use with mounting rings so I can balance it properly.

I pointed the telescope towards Polaris and had no trouble splitting this binary at 31x. Later I also observed the Ring Nebula M57. It was not difficult to find, even though I had not mounted the Rigel QuikFinder. At 31x it was not more than a tiny smudge from my light-polluted patio. Adding a UHC filter improved the contrast somewhat.

Airplane!

An airplane heading for SJC while imaging the M81/M82 mosaic. This is a single 60 second frame through the V filter.

NGC 1502

NGC 1502 on December 3, 2004. A 10 minute exposure (20x30s) through a V filter using the 80ED. The camera was cooled to -15°C.

I also imaged it with an I filter. I still have to perform photometry.

The Double Cluster in Perseus

NGC 869 and NGC 884. Mosaic of two images taken on December 3, 2004 through a V filter with the 80ED telescope. One of 57x30s and the other of 31x30s. The camera was cooled to -15°C.

Click the image to see the full mosaic.

Equipment

Telescopes

• Oberwerk 10.5x70mm Ultra Series binoculars. I selected 10.5x instead of the more common 15x because I assumed this would allow me to use it without tripod. It also has a larger exit pupil distance. However, although these are great binoculars, I regret not buying the 15x variant instead. It's too heavy to not use with a tripod anyway, I find the 10.5x magnification too low and, more importantly, the exit pupil diameter of the 10.5x variant is too big. Since 2010 I use it with an Orion binocular mount on the Orion XHD Paragon Plus tripod I originally bought for the 80ED. Its weight is really pushing the limits, especially when viewing near zenith, because of the poor design of the binocular attachment on that mount. This binocular mount is far from perfect, but it does make observing with the binoculars more convenient;
  
• My main telescope is a 254mm f/10 Meade UHTC LX200GPS. It has the standard electrical focuser and primary mirror lock. A nice feature of this telescope is the upgradable firmware (older versions and history can be found here). To reduce the slewing noise and load on the gears, I use a maximum slewing speed of only 1 degree per second;
  
• For wide field imaging, I have an 80mm f/7.5 Orion 80ED. I usually mount it on top of the main telescope;
  
• 7x50 binoculars of an unknown brand bought mid-nineties. The optics were never properly aligned, but I wasn't actively observing in this period anyway. In 2001 I picked up the observing again but when I bought the LX200GPS, a GOTO telescope, I stopped using it again. I replaced it in 2008 with 10.5x70mm binoculars;
  
• 115mm f/9 Newton telescope bought in 1981 through Gerard Keijzers from N.J.R.S for a 10% reduced price from Ganymedes in Amstelveen, The Netherlands. I still remember my excitement when Gerard helped me setting up this telescope and I viewed through its 20mm eyepiece for the first time. It has a aluminum OTA and equatorial mount on a wooden tripod.
  It's a decent telescope but it has its flaws. The equatorial mount is inadequate for the OTA. The slightest breeze or touch causes the OTA to wobble and it takes several seconds to dampen. Also its 30mm finder is of very poor quality and I rarely used it. The telescope is rebranded as "Vesta", but I think it is a predecessor of the now discontinued Celestron Firstscope 4.5" Newton on a CG-3 mount (model 31044) with .965 inch Huygens 20mm (magnification 45x) and 6mm (magnification 150x) eyepieces. Later I also added a Huygens Mittenzwey 9mm (magnification 100x) and a Symmetrical Ramsden 4mm (magnification 225x). The ones I used most were the 20mm and the 9mm eyepieces. From my old drawings it is clear that my eyes and the telescope optics once were pretty good. I did see the casinni division and a cloud belt on Saturn with it for example. Nowadays the mirrors are very much in need for a recoating;
  
• 40mm refractor. I was really my brother's, but I used it for many years instead. It had a cardboard OTA, wooden ALT-AZ mount and probably because of the heavy use by me its achromatic doublet developed an air bubble between its crown and flint lenses which made it a poor performer. I also ruined the single Huygens eyepiece at one point, but continued to use it. In addition I ruined most of the negatives of my family's pictures in my Sun spot viewing sessions (usually at sunset), but I don't think anyone but me ever realized that.
  

Cameras

• SBIG ST-7XE NABG CCD camera. This is a dual CCD camera with a full-frame NABG 765x510 (9x9μm) pixel Kodak KAF-0401E imaging CCD and a full-frame ABG 192 x 164 (13.75x16μm) pixel TC-211 CCD tracking CCD. Mine can cool up to -40°C from abient without using the water cooling. I usually set it to -35°C. In San Jose, CA, this means that the CCD temperature is around -25°C (-13F) on a "cold" winter night, and around -15°C (5F) during summer.
  
• SBIG CFW8A color filter wheel. This automatic filter wheel has room for 5 1.25 inch filters, which is 5 too few, because besides the standard R, G, B and clear filters (and an empty slot), I also own Bessel V and I filters for photometry and narrowband H-alpha, OIII and SII filters.
  
• SBIG AO-7 Adaptive Optics. This is a high speed tip-tilt mirror system. My laptop limits it to 30 corrections a second. I usually use it at 7Hz - 15Hz.
  
• Philips ToUCam Pro webcam for planetary imaging;
  
• Meade Superwedge. Instead of the standard knobs, I use replacements from Scopestuff so I don't have to use tools.
  
• Meade f/6.3 and f/3.3 focal reducers.
  
• Cable (Radioshack)
  
• Jumpstarter (Walmart). I never even tried to use the telescope with internal batteries. From the start, I used a 12V 17AH battery.
  
• 25ft serial cable for connecting the telescope to the laptop (Radioshack).
  
• Springy Thingy (parts from Home Depot)
  
• Pizza pan. I found it a pain to try to put the telescope on its tipod for ALT-AZ. As I didn't want to spend $95 on a scopesaver table, I bought a $2.95 pizza pan instead, drilled an off-center hole in it and marked the outline of the telescope base on it.
  
• Dew shield (Orion)
  
• Quick Rigel finder
  
• Collimation thumbscrews (Scopestuff)
  
• Balancing kits and weights (Scopestuff)
  
• Dew heater. I bought the convenient Dew Buster. To recover the costs, I made all the heaters (telescope, finder and eyepiece) myself.
  Case (JMI).
  
• 350 Watt inverter (Walmart).
  
• The next thing I will buy is the ASO optical cleaning kit. After almost one year of use, the corrector of the SCT is dirtier than my car's wind-shield.
  

I generally use this equipment in the following combination:

• Telescope - focuser - camera
  This combination fits through the forks and results in a f/10 system. The image scale is 1.028"/pixel??? in 1x1 binning mode and field of view is 10'x9'.
  
• f/6.3 reducer - focuser - camera
  
• Focuser, F/3.3 reducer, 15mm spacer, camera
  
• Focuser, F/3.3 reducer, 30mm spacer, camera
  This results in a F3.3 system.
  
• Telescope - focuser - AO-7 - camera
  F/11.3???
  
• Telescope - Focuser - f/6.3 reducer - AO-7 - camera
  This results in a f/7 (1774mm) system. The image scale is 1.04"/pixel in 1x1 binning mode and the field of view is 13.3'x8.8'. 1.033avg-1.030+1.035??
  
• Telescope - Focuser - f/6.3 reducer - 15mm spacer - AO-7 - camera
  

The image scales were determined using actual images. I used the formula:
focal length [mm] = 205 * pixel size [micrometers] / image scale ["/pixel]
to compute the effective focal length.

My reasons for not using other combinations,are:

• Telescope - AO-7 - camera.
  This combination fits through the forks, but without microfocuser it is pretty useless.
  
• Telescope - f/6.3 reducer - focuser - AO-7 - camera
  This results in a f/4.9 (1253mm) system. The image scale is 2.098"/pixel??? and the field of view is 26.7'x 17.8'. This combination results in off center vignetting with a brightness difference of about 30%. For this reason, I will not use this combination anymore.
  

Problems

Although the LX200GPS is an incredibly value for the money, it does have a few problems.

• The fork mount is heavy. swing
  
• The OTA of my telescope is not mounted parallel to the fork arms. When I put it in polar home position and rotate the telescope back and forth in RA, I will never find position (by adjusting the declination) where the stars move around a center.
  
• The optical axis is not aligned with the mechanical axis of my optics. When I use the f/3.3 reducer or the f/6.3 reducer with a big spacer, the vignetting is off center. Coma is visible in one corner when I use the f/3.3 reducer.
  

Hardware Issues

A list of issues encountered:

• The OTA of my telescope is not mounted parallel to the fork arms. When I put it in polar home position and rotate the telescope back and forth in RA, I will never find position (by adjusting the declination) where the stars move around a center.
  
• The optical axis is not aligned with the mechanical axis of my optics. When I use the f/3.3 reducer or the f/6.3 reducer with a big spacer, the vignetting is off center. Coma is visible in one corner when I use the f/3.3 reducer.
  

• Internal reflection caused by the visual back.
  
• Telescope didn't fit in the JMI case.
  
• The handy microfocuser mounting thumbscrews that were included with the JMI case ruined the original visual back and many of my images.