Observing Tips

Here are some tips and tricks that I've learned over the years.

Seeing and Transparency Scales

This is handy! From

Astronomical Seeing (Atmospheric Stability)

  1. Severely disturbed: Low powers unsteady
  2. Poor: Medium powers unsteady
  3. Good: High powers unsteady
  4. Excellent: High powers soft
  5. Superb: All powers steady

Transparency (Clarity) Scale

  1. Mostly cloudy
  2. One or two Little Dipper stars visible
  3. Three or Four Little Dipper stars visible
  4. Five or Six Little Dipper stars visible
  5. Six Little Dipper stars + Milky Way with averted vision
  6. Milky Way + M31 + seven Little Dipper stars visible
  7. M33 and/or M81 visible

This is a handy guide as often when I'm observing I want to make a note of the seeing and transparency but I always "gut" feel it as 1-5 for seeing and 1-7 for transparency. This gives me a bit more of an objective way to rate it.

Note: my main telescope is an 8" Meade SCT, so for me low power is with my 32mm Plössl (64x), medium power would be my 15mm Plössl (135x) and high power would be with my 8mm Plössl (254x). I have had nights where the seeing was a 5 and the transparency was a 7 - those nights are super-rare and to be treasured!

I'm just recording this for future reference. Hopefully it will help others as well!

Messier Marathon

Once every year at the vernal equinox, all 110 of Messier's deep sky objects are visible during the course of one entire night. In the northern hemisphere, the date usually falls in late March. This is a grueling test of an astronomer's knowledge of his telescope and the sky. Your going to need a 6 inch or larger telescope and some sky charts to find your way around. To prepare:

  • Be well rested!!!
  • Ensure your equipment is in proper tune (collimate if required)
  • Pick a dark sky site away from light pollution
  • Pick a site with good views of east/west horizon (little/no trees)
  • Dress warmly, and bring some snacks
  • Have extra batteries for red flashlights, laptops, dew removers, etc
  • A battery powered alarm clock or other device to wake you up after nap time is over

Prepare to arrive at your observation site at least an hour before sunset (or even earlier if your telescope requires a long setup and cool down period). Get your charts and your observing area laid out prior to dusk. Then, get ready to rumble!

Viewing Order

This viewing order is based on Don Machholz's book The Messier Marathon Observer's Guide. The hardest part of the Marathon is the beginning and the end. M77 and M74 are dim and will be tough to locate at dusk. Do the first 10 objects as quickly as you can. After that, you can pace yourself through to object 48 (M3). At this point, it should be around 10:45PM. You should take a 30 minute break for a snack and perhaps a trip to the bushes. Resuming at 11:15, you can jump into the Virgo Cluster (be careful! The next 14 objects are all in the same area, and there's a number of NGC objects that could confuse you. Use your finder charts, and ensure the stars surrounding your objects are correct!) and go until object 90 (M16). At this point, it should be around 1:30AM. The remaining 20 objects should just be starting to rise, so you can take a 90 minute nap if you wish (USE THAT ALARM CLOCK!). Be ready to go at 3:00AM and bag the remaining objects. Again, the last few are going to be the toughest, as dawn approaches. Do your best and have fun!

My best advice is to PREPARE! Do a dry run of the first objects a week or two in advance. Also, ensure you know the Virgo Cluster area very well. Finally, if you're seriously dedicated, do a dry run of the morning objects as well a week prior. With planning and patience, you can join an elite group of amateurs that have completed Messier's lifetime* of work in just one night!

* - minus, of course, all the comets he found!


The following article was written by me (Rick Towns) in September, 2000. I thought it would be great to put it up here for posterity, as digital cameras were just becoming the norm, so the focus of my article is using film cameras. Imagine! (BTW: I'm still no good at astrophotography!)

Tips For Great Astrophotos - by Rick Towns

I am certainly not well known for my astrophotography abilities; however, I have attempted some of the more basic shots through my telescope. I have found simple resources on this part of my hobby are scarce, and I thought it would be beneficial to have a simple resource available that would allow a novice or amateur astronomer to take some decent astro photos without having to read a big book cover to cover.


A great deal of detail regarding astrophotography can be found in various books, so the purpose of this section is to give you a general run down on the types of equipment you may need. For more information, I recommend "The Backyard Astronomer's Guide" by Dickinson & Dyer. It goes into much more detail than we do here.

Olympus OM-1 SLR CameraOlympus OM-1 SLR Camera Obviously, to take pictures of anything involves getting a camera. Astrophotography demands more than grabbing any camera and pointing in skyward. It involves getting the right camera for the objects you wish to photograph. Generally speaking, you need a camera that will a) give you manual control over when the shutter opens and closes, b) runs without battery power (fully manual) and c) can connect to a telescope or camera tripod. Specifically speaking, an excellent choice for all of these items is the Olympus OM-1 SLR camera. It is fully manual and can be purchased used for usually under $200.00. There are various other camera makes that also meet some or all of the requirements, but make sure you know what the camera's capabilities are (ask the sales person) before buying. One additional item you'll want to buy with the camera is a remote shutter release cable. This will allow you to open and close the shutter without touching the camera, and inadvertently ruining your pictures with the vibrations this may cause.

Once you have the camera you need, the next step is to decide how to take your pictures. For instance, if you want to take a picture of star trails, all you'll need is a camera tripod and good lens (i.e. 35mm will do fine). If you're more interested in galaxies or wide angle views of the sky, a piggy back mount for your motorized telescope is required. This allows you to mount the camera on the telescope, but still take the pictures through the camera's lens. Finally, close up pictures of the moon or planets, or detailed deep sky objects will require photography through the telescope. This requires a t-ring adapter that will fit your camera, and optionally a variable length tele-extender which allows you to use an eyepiece (for magnification) with the camera.


Fujifilm 35mm CannisterFujifilm 35mm Cannister Choosing the right film for your subject is important, however generally ISO200 or ISO400 film will take beautiful pictures. 200 film takes longer to capture the image, but has less granularity and finer detail than 400 film. 200 is good for bright objects such as the moon or the planets. 400 film is better for dimmer objects that require the shutter to be opened for extended periods of time, and you want to capture the image quickly but effectively. A good example would be a galaxy or a globular cluster. Once you master some basic pictures, you demand for higher specification film will grow. Again, "The Backyard Astronomer's Guide" is an excellent resource of information regarding different film types and speeds.

Exposure Times

This is the hardest part of astrophotography. Keep the shutter open too long, and you over expose your subject, too short and you get nothing but inky black. I have found that photos of the Moon or Jupiter on ISO200 film require exposure times in the 1/60th to 1/500th of a second range. I have just loaded up my Olympus OM-1 with ISO200 film, and I will build a more definitive table of exposure times very shortly.

TIP - If you get your film developed at the local photo mat like I do, take a few regular pictures (of the bushes, or your wife, etc) at the beginning of a role of film. Use the first 3 exposures in this manner before taking astro photos. The reason for this is that most automated photo processing machines need some "normal" pictures to determine the frame length while developing. If you don't do this, your picture may not be developed the way you'd expect. Also, request they DON'T cut the film, that way you can get reprints made if the film is not developed to your liking.

Focusing Techniques

Kendrick KwikFocusKendrick KwikFocus Focus Template This is by far my favorite part of this page. I believe this will only apply to users of Cassegrain and Reflector type telescopes. What I found out is that if you take a piece of cardboard and cut it in a circle to match the diameter of your telescope, you can use it to get tack on focusing of any object. The idea is that you take the circular cardboard piece, and cut 3 holes in it. The holes should be 50% of the radius of the circle in size, and should be placed 120 degrees apart on the circle. Finally, the center of the holes should be 50% out from the center of the circle. You'll wind up with something similar to the picture to the left.

Once complete, place the template over the end of the telescope. This will be the open end of a reflector (i.e. Dobsonian or Newtonian) or over the glass corrector plate of a Cassegrain (i.e. Schmidt or Maksutov). With the camera mounted at the focuser of the telescope (either for prime focus or eyepiece projection - NOT piggy back photography), look through your SLR camera's view finder. You should see three images of your subject (i.e. the Moon). Adjust the focus on the telescope until all three images merge in the middle into one image. Once this is complete, carefully remove the focus template and look through the camera again to ensure the object is centered. It should appear much brighter than it was with the template in place.

That's all there is to it! Now just take your photo and you're ready for your next object. I would recommend re-using the template before every picture, as your telescope could shift out of focus while moving it around or adjusting the camera. You can actually purchase these focus templates, although I am unsure of the cost.

I will post more tips and tricks as I learn them. If you have any suggestions on taking astro photos, please e-mail me at: [email protected].