Tuesday, August 31, 2010

Cheap hardware

I've lately noticed that Small Parts has discounted a lot of their inventory in Amazon's Industrial and Scientific store. As long as one gets free shipping with a $25 order or with Amazon Prime, the prices are lower than at my local hardware stores (and if one counts the gas, much lower). For instance, I needed two 1/4-20 knobs for a tailgate. Small Parts had a pack of five nice three-lobe female 1/4-20 knobs for about $1 (one can browse all their knobs by searching for "1/4-20" dimcogray). I needed three #6-32 collimation screws for a laser collimator. I got five really nice mil-spec stainless steel screws for a total of 30 cents (their mil-spec inventory seems really highly discounted)--my local hardware store has zinc plated #6-32s for about 12 cents each. Yesterday I needed two socket cap #6-40 screws for one of my Daisy RDFs, so I could adjust them by hand. A pack of fifty nylon socket cap screws was about fifty cents. (I am guessing that at Lowes they would have tried to sell them for about $0.75 for two, and I'd have to pay for gas.) I also bought two timing belts and timing belt pulleys for a $1.63--I'd have paid about $10 plus shipping at SDP-SI.
A lot of these items are marked as heavily discounted, by up to 90%, so I don't know how long this will last. They can't be making money on a lot of these. It's weird to shop online for items under 50 cents.
My currently going projects are: (a) digital setting circles for my 13" and (b) equatorial platform for the 13" (that's what the pulleys are for). I think I will also make a parallelogram mount for my binoculars.

Sunday, August 22, 2010

Hectospec M31 catalog for AstroInfo

If anybody other that me is using the free AstroInfo for PalmOS, I've uploaded a catalog of objects up to mag 16.5 in M31.  The catalog is based on the one on this great site, which is worth visiting whether you have a Palm PDA or not.

Sunday, August 15, 2010

Chalkboard paint

I painted the inside of my 13" Coulter Dobsonian with Rust-Oleum latex brush-on chalkboard paint ($10 at HomeDepot;  the two coats I applied used up about a quarter of the 30 ounce can), because I heard that chalkboard paint produces a nice and flat finish.  By and large, it did.  In some areas it wasn't quite as flat as ideally, but those were rougher areas, so the light will be scattered there anyway.  It's the flat and smooth areas that are most important.

I will let it try for a while before putting the optics in, and then there'll be lots of moon out, so it'll be a while before I can seriously try it out.

Friday, August 13, 2010


I've never had much luck with meteor showers.  It's always been either cloudy and I wouldn't go out, or else I couldn't see anything (I've seen the occasional meteor on other occasions).  But last night I took my kids out to my dark site outside of town.  It was promising that as we were driving down, my daughter saw one out the car window.  On location, she saw two more, and I saw two (maybe not the same ones).  They were nice and bright.  Unfortunately, my 5-year-old son didn't see any, and he cried about that.  But I showed him the Milky Way and that comforted him.

I had sent out an email to my club that I was going, and when I arrived there was already a couple there, in conversation with a suspicious police officer who was wondering what we were going to be doing, how many people were going to be there, and how long we would be.  He also id'ed them.  As soon as I arrived, he seemed to get much less suspicious, and after a question or two, he drove away.  But he kept his car about 1/3 of a mile away with headlights on, I think to keep an eye on what we were up to.

I took my 8" Coulter along, and we also looked at M8, M13, M20, M22, M57, a bit f the Veil, and the Owl/ET/Airplane Cluster (which I've noticed always pleases people).  I couldn't find M81/82, because it was low in the sky, and in Waco skyglow, and there weren't enough naked-eye stars in the vicinity to quickly star-hop to it (I could have done it slowly field-by-field, but not with the kids and the two other people waiting).  Not having used my 8" Coulter much for deep sky stuff recently, I had forgotten that it is a rather nice scope.  I appreciated the crispness of its F/4.5 optics--better than my F/4 travel scope with its cracked and scratched mirror.  And I am quite happy with the helical Crayford focuser, though I need to put in some star nuts to make sure the bearings don't rotate out of the way.

Wednesday, August 4, 2010

My 8" F/4 travel scope: Traveling

I visited my parents in BC, Canada, and finally got to do air travel with my travel telescope, which is what it was designed for.  The eight pound mirror box was in my backpack.  The rest of the scope (another 8.5 pounds) was in my suitcase, as were my eyepieces.  It made it just fine.  On the way out, I had to open the mirror box cover up for TSA.  They asked about a blackish stain on the mirror box, which I said was either paint or a table saw burn (closer examination later revealed that it was the latter).  No questions were asked on the return.

The eyepieces were packed mostly in bolt cases, and then in bubble envelopes, and a soft bag that was inside my and my son's big suitcase.  There was also my home-made laser, which I put in a cardboard box that I labeled "telescope collimation laser" because I knew it might puzzle TSA.  In both directions, the suitcases ended up with a card from TSA saying they had opened it.  They kind of messed it up on the return leg, not zipping up the inner bag with the eyepieces, and putting the lightshield randomly in the middle of the suitcase, rather than tucked in by the bearings to prevent damage.  But no damage was done to anything.

The scope did very well on Saturna Island.  I used to think it was no good for planetary purposes, but one night it actually did decently on Jupiter and the moon at 200X (TMB/BO 6mm + Barlow cell).  I had hoped for darker skies, and I thought that with the moon rising at around 10:30 pm, I'd get some dark sky time before moonrise, but I forgot that up north in the summer it only gets dark really late--like 10:45 pm.  Moreover, with the moon rising over the sea, even when the moon was very low, it was not covered by anything.  Nonetheless, my parents and sister liked the E.T. / Owl Cluster, and several other deep sky objects, and both Jupiter and the moon were hits.  Maybe next time I visit, I will do a public star night.

I also got to see some nice killer whales through the scope.  The scope works quite well for terrestrial purposes at 27X (30mm Rini)--the whales were quite some distance away, but they were very clear.  And the mount is nicely solid for daytime use, and one doesn't need to worry about objects slipping from the field of view.

I did find that with my 13mm Hyperion, the balance was off for elevations below about 30 degrees, even with the springs attached.  For low elevation work, I ended up hanging a small drawstring bag with about one to pounds worth of stuff inside.  I hung it from the wingnuts holding the strut to the mirror box.  I like this way of doing a counterweight--I can just travel with a drawstring bag, and then fill it at the destination with whatever heavy objects (rocks, other eyepieces, whatever) I can find, and the counterweight doesn't add to the travel weight.