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Posts Made By: Ed Zarenski

January 18, 2003 12:11 PM Forum: Equipment Talk

Book suggestions

Posted By Ed Zarenski


I agree with the others that say one book doesn't do it all. Charts that show the level of detail you'll need aren't usually arranged by constellation. I have not seen NSOG. I tried for about three months to buy it and could not find copies available.

I've taken Sky Atlas and lightly drawn in the constellations. But I've also taken it and photocopied sheets showing a constellation and wrote all over the photcopies. I've got so many notes written on sheets now that my outdoor charts are my 50 pages of photocopies.

These questions about charts and reference books are now in several forums. I believe you need both good charts and good references. Even a good pocket reference. I'm sure there are a dozen books I don't even know about, and I now own a bunch I haven't yet written about, but I have written about a whole bunch. Check these out

I recently picked up Nightwatch, it's nice, has a lot of great info, but limited. Binocular astronomy by crossen is another good one, not just for binoculars, but still won't give you the detail you need. I now also own Uranometria Charts. Detail is impressive, but very large, overwhelming if you think Sky Atlas is big. Two volumes over 250 pages each to cover the whole sky. Cambridge Star Atlas will not give you enough detail for an 8" scope. Sky Atlas will just get you close. The Lughinbuhl and Skiff book mentioned above is a pretty good reference. There are others more detailed, but maybe to much information.


January 30, 2003 05:13 AM Forum: Deep Sky Observing

Light Cup Hot Tip: Clusters Clusters

Posted By Ed Zarenski


I know there are clusters grouped closely in Monoceros. The area just north and east of The Rosette is loaded with clusters. Within a 3° circle you will see 5 or 6 clusters, dominated on the southwest by the cluster 2244 at the center of the rosette nebula.

The area at the east end of Cas, Ssarting with M103 and just north and east includes 3 more bright clusters, 1 faint, TR1, 654, 659, 663. The last three impressive in binoculars.

Also in Cas, just north and west of Y Cas is a small group of three faint clusters including King14, the other two, ngc133 & ngc146 are not shown in SkyAtlas 2000.0. these are a tight group about 1/2° north of k Cas.

There are five more clusters just south of this area in Cas all within 2°, between Y Cas and B Cas. Bounded on the east by NGC 225 and on the south by NGC 129 and on the northwest by 12 Cas. The other three clusters, not shown in SkyAtlas 2000.0 are ngc136 ngc103 and St24

A little further east from Cas, you should be able to capture Stock 2 at the same time with the double cluster in Perseus at the very limit of 3°. Very impressive.

some of these are pretty faint. good luck

January 31, 2003 09:14 AM Forum: Equipment Talk

Which mount is which???

Posted By Ed Zarenski

A smaller mount, the Orion EQ2 is exactly the same as the Celestron CG3. I own both of these.

The Orion SVD Sky View Deluxe (not one you mentioned) is more substantial than the above but it is not the equivlant of a CG5. I own both of these.


February 22, 2003 04:57 AM Forum: Equipment Talk

Collimation question

Posted By Ed Zarenski

Could be a slight amount of mirror shift.

February 22, 2003 08:38 AM Forum: Equipment Talk

HD-F2 Tripod?

Posted By Ed Zarenski


I use this HD-F2, the smaller of the two paragon tripods, with my 7.75# binoculars. The binoc weight is shaky if I have the center post extended to a full 6'6" height, but is just fine if the center post is down. The center crank friction knob holds just fine. The Altitude friction knob, I have tightened down probably way past the point it is intended to be used. I have taken two hands and twisted this thing as tight as it will possibly go. This allows me to point the binocs to any altitude in the sky I desire. .
I have two beefs with this tripod. 1st the helical leg locks. Almost impossible to loosen in cold weather. So on numerous occasions when breaking down, I've had to put this tripod in the back of the van fully extended. 2nd, if you have the azimuth lock tightened down and you grab the pan handle to swing left or right, the head will begin to unscrew.
I like this tripod because it's tall, sturdy and inexpensive. I've never had an accident with it because I'm aware of it's features. It serves me well for my heavy binocs and I continue to use it for that purpose. I used to mount my ST90 on this tripod and still do sometimes, like this past week on vacation up in ski country. It's more than enough tripod for the 5# ST90. Just like the binocs, if you mount your scope with the pan handle facing forward towards the objective lens, you can point this thing up to zenith. You can control the spread of the legs on this tripod. I bought the Orion pouch for this tripod, makes it easy to carry around. I have the pouch for the ST90. I can throw the 2 pouches over my shoulder and comfortably hike a half mile up the raod to a high field.

I've been using the Orion Slo Mo for a few years. I originally bought it to mount a small 2# 60mm refractor on a camera tripod to give me some control. I now use it much more often to mount binoculars for the same control motions. Works great, except for the last few weeks in zero degree temps. the dials are nearly impossible to turn, but it still worked with difficulty. Otherwise this is a great accessory.


February 24, 2003 10:35 AM Forum: Equipment Talk

Using Phillip's Planisphere (question)

Posted By Ed Zarenski

The easiest way to get your bearings with a Planisphere is this. Set the clock dial to the day/ month dial for the time/day/month you want to observe. Now hold the planisphere up in front of you while facing south. The time/day month setting will show you exactly whaty the sky looks like at that time. If you want to see what the sky would look like at sunrise or sunset, set that time of day to the appropriate day/month and it will show what the sky looks like at that hour.

The bottom of the planisphere window represents south. The rivet hole represents the north star, Polaris. the line up thru the center of the planisphere should show you the stars right up thru the meridian in the sky. When facing south with the planisphere in hand, left is east in the sky and on the planisphere.

Its a bit more difficult using the planishere to find things in the north circumpolar area.

Remember this. the planisphere is trying to place a map of a half circle section of the sky on a flat surface. If you could bend the planisphere into the shape of a bowl, it would take on the shape of the sky overhead.

hope this helps, edz.

February 24, 2003 01:38 PM Forum: Chinese Optics Imports

Burgess 25x100 vs Burgess 20x80

Posted By Ed Zarenski

Price aside, and all else being equal, meaning quality of glass, prisms, coatings, mechanical operation, etc., in my mind I say go for the magnification. The exit pupil of these two choices is the same, and if you want you can stop down the 100s to get a higher resultant system f and smaller exit pupil which may improve contrast, chromatic abberation and resolution.

The 100s will provide greater potential resolution and more light gathering power but the 25x is what allows you to utilize more of the potential. 25x80s would allow you to see more than 20x100s. It's not the increase from 80mm to 100mm that's going to show you the greatest leap in performance, it's the jump from 20x to 25x, if all else is equal. Of course, rarely is all else equal. Take note of Erik's comment on size and weight and what is required to mount this instrument.


February 27, 2003 07:00 PM Forum: Astro Binoculars

Prof. Zarenski Writes the "Book" on Binos

Posted By Ed Zarenski

Thank you Milt. Comments gratefully accepted.

I think the reason we visit sites like these is to engage in information sharing. You might have noticed that a few paragrahs in the articles had their beginnings here in the Forum.

I've found that I can share a wealth of information by writing articles and CloudyNights provides me the forum to share that level and breadth of detail. I hope your endorsement and others comments lead more to benefit from my efforts.

I hope you all find my efforts worthwhile.

Clear Skies, and if not, Cloudy Nights.


March 2, 2003 03:54 AM Forum: Equipment Talk

buying a scope for school

Posted By Ed Zarenski

I would not but a Dob for use with a K-5 group of kids. Are you the science teacher? Are you going to man the scope? Who is going to adjust the mirrors when they go out of allignment?

Children in this age group have an attention span of only several minutes. They do not have the patience to sit arround and wait every time the scope needs to be recentered. You need a scope with slo motion dials or one that can be locked on to an object and allow a whole group of kids to observe before you move on the the next object.

I have been teaching kids in K-8 for four years now. In that time I've taught over 1000 kids and their parents. Although I haven't used any Dobs, I have used Newts and Refractors without tracking motors and several with tracking motors and plenty of binoculars. The binoculars get used the most by the kids because they can easily get moved around. The scopes that get used the most are those on equatoral mounts with slo motion tracking or with motors that can get locked on after acquiring an object. It's not even the big scopes. The kids aren't affraid to go up to a 90mm scope and turn the dials to get back on an object. But if they can't see something in 60 seconds, they're gone, off to the next thing. A big scope is overwhelming to a small kid. They don't seem to want to mess around with something that is as big as them.

FWIW, I would look for something a lot smaller and a lot more usable by kids before I went out and bought a Dob. Kids don't need big they need easy. Don't get them frustrated early on. Keep them involved.


March 2, 2003 04:12 PM Forum: Equipment Talk

buying a scope for school

Posted By Ed Zarenski

So Allen,

Now let me offer you a link to CloudyNights for Teaching Kids Astronomy. You may find something you will be able to use in this collection of posts. Two years ago CN ran a little contest and asked user/teachers to submit an article on how they teach kids. I submitted. I didn't win the contest, Anthony Lutton won. Here you will find a tremendously varied collection of articles on how people approached keeping kids interested at the scope. My post is titled "A complete Astronomy Presentation".

Page down to the section Engaging Kids at the Telescope

I hope you find all this stuff useful.