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Haas Double Star Book now shipping

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#26 fred1871

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Posted 31 August 2014 - 03:21 AM

 

Last night I decided to take my new Sissy Haas book out for a spin. The transparency was 8/10 and the seeing was 6/10 on Pickering. I was using my 80mm Mayflower on a Losmandy GM-8 with Gemini 1. Observations were made with a 5mm Type 6 Nagler with TFOV of 20.5’ and a magnification of 240X. The GoTo’s were putting the objects in the FOV of the eyepiece each time, so it promised to be a good night.

 

aside from calling out bob's individual star observation reports, which are well done in an informal style, i wanted to point out that he's working at an exit pupil of 0.33 mm, which is also my favorite for close systems.

 

planetary astronomers sometimes try out that double star thing, set up with their usual 2 mm exit pupil, and wonder what all the fuss is about.

 

and ... oh, yes ... double star astronomy with an accurate GoTo system? -- priceless.

 

Bruce, an exit pupil of 0.33mm is what I use for the very tighest systems with 140mm aperture, but I certainly don't use it for everything.

Many doubles separate with less power, and many of them look better with less.

 

Regarding planetary observing - back in the day when I did this with a 10-inch Newtonian, I did not use ~125x (2mm exit pupil) - common magnifications were more likely 250x - 360x with that aperture, exit pupils of 1.0mm to 0.7mm. With a 9-inch refractor on Mars (1980s oppositions), 400x was about right (0.6mm) on the better nights (560x occasionally - 0.4mm exit pupil). 

 

Saturn with a 7-inch apo - 180x -360x (1.0mm to 0.5mm). With my current 140mm refractor, Jupiter is best in the 120x-200x range (1.17-0.7mm exit pupil); Mars will take more power, 230x is good (0.6mm).

 

Overall ? - magnifications I used were similar to those other experienced observers used. And not a lot different from what I use on double stars, though on doubles I do go higher when needing more apparent size, something that can be done with points of light more readily than with contrast features.



#27 drollere

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Posted 31 August 2014 - 02:22 PM

fred, you should understand that you make me weep when you talk about submil exit pupils on planets. i almost never have seeing here along the north california coast that allows such impudence.

 

even so, i've been toured around the planets by other people showing off their scopes, and your standards are unusual in my experience. (but again, most of them also live out my way.)

 

and you're right, as i said ... i use 0.33 (or less) "for close systems".



#28 rcwolpert

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Posted 16 September 2014 - 02:08 PM

 

Last night I decided to take my new Sissy Haas book out for a spin. The transparency was 8/10 and the seeing was 6/10 on Pickering. I was using my 80mm Mayflower on a Losmandy GM-8 with Gemini 1. Observations were made with a 5mm Type 6 Nagler with TFOV of 20.5’ and a magnification of 240X. The GoTo’s were putting the objects in the FOV of the eyepiece each time, so it promised to be a good night.

 

aside from calling out bob's individual star observation reports, which are well done in an informal style, i wanted to point out that he's working at an exit pupil of 0.33 mm, which is also my favorite for close systems.

 

planetary astronomers sometimes try out that double star thing, set up with their usual 2 mm exit pupil, and wonder what all the fuss is about.

 

and ... oh, yes ... double star astronomy with an accurate GoTo system? -- priceless.

 

 

Thanks for the comments, Bruce.  Since I made those Aug 17th observations, I've been in the process of moving my household to two different locations - one on the east coast of Florida, and one here in the San Jose, CA area. Just for the record, I would not recommend this type of move to anyone. It's been one heck of a month, and I miss those double stars!  All my telescopes and mounts went to the Florida location except for the 80mm Mayflower, which will now operate on it's own mount, so I can kiss the GoTo's good-bye for a while. It's back to star-hopping, which has it's own rewards, but on the really positive side, I'm now using a transportable set-up and will be observing from much darker sites.

Back to the exit pupils, while the 0.33 is also my favorite for close systems (and some not-so-close), I do use several different eyepieces depending on what's being observed and the quality of the night. Unfortunately, I still need to meet the moving van on the Florida end of the trip, so it might be another 2-3 weeks before getting back to observing and using the Haas book. I'm having serious double star withdrawal symptoms!

 

- Bob



#29 TG

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Posted 17 September 2014 - 07:30 PM

I got this book but I have mixed feelings about it. The small prose section at the front is all fine and dandy but the rest of the book is in a woefully dated format. There's a reason nobody publishes tables in books any more and that's what it is, a tabulated list of double stars. Much better to have it available in electronic form where it could be searched and cut-n-pasted easily to make building observing lists easier.

 

Alternately, the author could provide an auxiliary website with the data in electronic form but then nobody would buy the book. :hmm:

 

Tanveer.



#30 fred1871

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Posted 17 September 2014 - 11:39 PM

Although it's a tabulated list, it's helpfully broken up into Constellation sections, which makes each section more easily used for an observing list.

 

It also represents a selection, and selections save a lot of time. And not everyone wants or needs a list longer than the 2,000+ doubles in this book. Because it's a selection it means you don't have to wade through huge numbers of objects. It generally includes all the showpieces for the constellation, and in most cases a good choice of the other doubles that might be interesting, assuming modest telescopes. I had the impression it was originally designed around 60-150mm scopes; then some extras, somewhat more difficult, were added.

 

 And for each double, you have basic data - not too out of date : often more recent and accurate than in the Cambridge Double Star Atlas lists -  and for a lot of the doubles, a brief description of its appearance in a moderate telescope, plus some brief notes from classic observing books. And unlike some observing books, it goes pole to pole - from Ursa MInor to Octans.

 

Overall, I think it's a useful work and I make quite a lot of use of it.

 

You've answered your own question on why it's not in digital form. :grin:

But, as with star maps, some like printed atlases, some prefer digital ones, and some of us use both. :cool:



#31 Rich (RLTYS)

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Posted 18 September 2014 - 06:02 AM

The book has more then its share of errors but still a very useful book which I would still recommend.

 

Rich (RLTYS)



#32 OrdinaryLight

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Posted 30 September 2014 - 01:48 PM

Is there anyone who has both Doubles For Small Telescopes and Night Sky Observer's Guide and could speak to whether they would be redundant or complement each other?

 

I have vols 1 and 2 of NSOG on route to me and understand that these include a list of double stars for each constellation similar to DFST. I plan on using NSOG more as a desk reference for session planning than as a field guide so maybe that's where the value of owning both might be found?



#33 fred1871

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Posted 30 September 2014 - 06:45 PM

I have both the Haas book and the NSOG volumes. They don't really duplicate each other. The NSOG listings are one line per double, with no date for the separation and PA measures, though with very brief colour notes.

 

Haas gives you more detail, including dates for measures, binary periods where these are known or estimated, and observer's descriptive notes.

 

I use Haas for double star listings in preference to NSOG, or the now very out of date Burnham, or the Cambridge Double Star Atlas where the maps are excellent but the listings inadequate and with too many errors. 

 

If double stars are more than a casual addition to your observing, Haas is worth having. The NSOG volumes are very useful for clusters, nebulae and galaxies, with photos and good descriptions from observing with various sizes of telescope. That's their real purpose - deep sky - and they do it quite well.


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