Posts Made By: Mike Ratcliff

Vincent,

Thanks for the info!

I've been to Grandview a couple of times. It is great.

What do you think of Joshua Tree National Park? Any recommended campsite?

Mike

Sarah,

To add to the numerous suggestions, having the largest field of view possible is very helpful for a beginner. I knew one beginner who's setup gave only 0.5 degrees true field of view (TFOV), and this was very frustrating. Even for experienced people this is too small.

You'll likely get a 25mm plossl eyepiece with your telescope. This will give you about 1.0 degrees, this is not terrible, but I would suggest getting more.

I would recommend at a minimum that you purchase a new plossl eyepiece 30mm to 32mm in size. This will get you about 1.3 degrees, doesn't sound like much improvement, but every bit helps. These can be found on astromart or through your telescope dealer for not much money. The 1.3 degrees is the most you can get with an ordinary 1.25" focuser on your telecope (8" f/6).

If you have the budget, you could consider going to a 2" focuser and getting an inexpensive 2" eyepiece like the BW Optik 30mm (about $100 new and $70 used). This eyepiece would give a whopping 2.0 degrees field of view and would make life much easier. The biggest problem with this setup is the weight and size of a 2" eyepiece will likely throw your scope off balance. You could then add counterweights. But the 2 degree field of view would be really nice for hunting around.

If you get the Rigel finder instead of the Telrad, then you'll have fewer balance problems.

Other suggestions:

1) binoculars, easier to find the brighter objects.
2) classic book by Rey on finding constellation star patterns
3) Book "Turn left at Orion" for finding easier objects.
4) Rigel finder.
5) Club star parties for help and for security at dark sky locations.

I used a 6" f/8 as my primary scope for seven years. It was wonderful.

Have fun!

Mike

I saw it years ago with 10x50 binos in a dark sky, during my first year of learning the sky. It was a very small object but a big thrill for me.

So, no it's not surprising that you saw it. But on the other hand it would be a challenge for a beginner who didn't know exactly where to look or what to expect.

So congrats on a nice catch!

Mike

Peter and all,

White is good except right around the eyepiece. Then the white reflects stray light toward your eyes while viewing. I painted my white tube dob black just on the upper 2 ft and only on the focuser side.

Your right about the visibility advantage. Once I gave a star party to a country school classroom that was having a special function that evening. The rural area was very dark and unlit. The teacher announced that my scope was on the basketball court (unlit). To my horror, the kids jumped up and ran out there at full speed before I could get out there, with their eyes still used to room light! Some of the first kids spotted it and shielded the horde away. If the scope were painted black, they would have surely run over it.

Mike Ratcliff

Doug is exactly right. And if I could elaborate...

What was so frustrating about some of the earlier threads that I was participating in was my inability to explain the seemingly magic ability of radiative transfer to leap into space, whereas convection (air movement) and conduction (direct contact) occur on much smaller length scales. The radiation (IR) is not affected much by the air itself, although water vapor and carbon dioxide absorb and reradiate some IR energy.

Radiative cooling to outer space still meets the requirements of physics: energy transfer from higher temps (earth) to lower temps (space). So with radiation transfer, the system has to be expanded to include outer space.

Radiative cooling is the primary means that the earth's surface and our lower atmosphere we live in cools off at night. Convection and conduction just try to even things out on a local scale between things that radiate strongly and things that don't.

Mike Ratcliff

Option 1. Ultimas are very well thought of. And the 30mm gets close to the widest field for a 1.25" focuser. Good for star hopping and finding things. Barlow is a great idea to avoid the small eye relief of the small 6 to 8 mm plossls. This sounds like a good option, although I haven't done this exact setup myself.

Option 2. I've had the TV plossls and they are very sharp. The 32mm would be good to add for wide field if you could squeeze that in. And I've had the Powermate which was very nice.

If you lean more towards deep sky, you could try a used Panoptic at 22mm or 19mm for around $200, then get a 12.5mm and a 9mm UO ortho $55 each for some occasional moon/planet entertainment and for globular clusters. UO orthos have about the best price/performance ratio in the world. Perhaps also 2x barlow could be squeezed in if you wanted the 6mm length for more serious planet watching.

I loved the 19mm Pan and the 12.5mm UO ortho with my old 6" f/8. The 19 pan was a real workhorse. Same field as the 25mm plossl but darker background due to higher magnfication. This was a good combination for many objects. The difference between a TV plossl and a regular plossl isn't really huge, but the difference between a 19mm panoptic and any plossl is astounding.

The 24mm Pan is even wider field but perhaps over your budget. It's newer and bigger, so used prices are pretty high.

Almost anything is better than the Meade plossl kit for $300 that are sometimes advertised here.

Mike

narrowband nebula filter

A list of Messier objects sorted by season is at:

http://www.seds.org/messier/xtra/similar/dataRASC.html

This is from the RASC (Canadian) list by Alan Dyer. Alan adds nice remarks on each object

Really helpful are that showpiece objects are denoted with !!. Summer !! objects are M11, M13, M17, M6, M7, M8, M20, M27, M57. I would personally add M22 and M24.

The only Autumn !! item in the RASC list is M31. I would add M15, globular in Pegasus.

The double cluster NGC 869/884 are famous objects that somehow got excluded from the Messier list and are spectacular autumn objects. Definitely would get !! from anybody.

So all of these are don't miss objects, if you haven't seen them yet it would be worth finding.

Mike

Howard,

If someone is standing exactly at the north pole on earth, then yes they can only go "south". Likewise, a telescope aimed directly at the celestial north pole (close to the North Star Polaris) can only go "south" from that point. Once the telescope is aways from the pole, then all directions are possible.

"Zenith" refers to straight up in the sky. If you have your telescope aimed straight up, you can still go to the east, west, north, south etc from that point. Just like most any other point. Moving north would be moving towards the north celestial pole close to the north star Polaris. (This is assuming your telescope is not set up exactly on the north pole).

Mike

Jim,

I heartily agree with your opinion on dark nebula. They are a blast at a dark site! My favorite right now is Barnard 86 in the Sagittarius star cloud above the spout of the teapot. Looks like drops of black ink on the starcloud background. It does take a very dark transparent night to see it at its best. B86 is small and would need a telescope I think, but not necessarily a huge dob.

Mike