Thanks Inertia,I cannot sleep part excitement part worry and trepidation.
Thinking about needing more eyepieces a cheshire thingy, lasers, and canisters for collimination maybe allen keys or tiny screw drivers...
Then red lights (hope they are bright enough to see snakes) carrying the scope then the base 15 meters to a clearing to get the best of the valleys sky view..
guess I will soon find out the next clear night what I can see with a stock standard 8 inch Dob. If I am the lucky one to get it.
Whille I was thinking about getting a SH 130p I wondered what I could use as a stand that wont wobble?
I have an old webber bottom half on a tripod maybe something like that with wood on top would be ok for you?
thanks for your help.
Pete
Sorry I din't reply to your PM, I have been laid up in bed for about 15 hours with gastro!
Firstly the fan issue. A fan is nice to have and in larger scopes is pretty much essential. Large SDM style scopes have multiple fans at the back and sides assisting with cooling, but in an 8" they become a non essential item. Neither 8" scopes i have used had fans and all worked just fine. If you find you get tube currents, a household fan sitting behind the mirror blowing air on the back of it will work fine, assuming the back of the scope is open of course.
With collimation, 35mm film can still be sourced relatively cheaply to make a collimation cap. Or the best bet is a cheshire. See: http://www.myastroshop.com.au/produc...sp?id=MAS-050A
or http://www.bintel.com.au/Accessories...oductview.aspx
for a couple of alternatives. The process is really simple once you have done it. One important thing to bear in mind is that collimation is a game of diminishing returns, getting obsessive about perfect collimation really is a waste of time in a small scope. If it is collimated about 95% right, the results will be inistinguisable from a perfectly collimated scope.
Red lights, Super Cheap sell I believe inexpensive red light headlamps that run of a AA battery and are nice and dim, from memory they are about $12. No they will not be bright enough to see snakes, if worried about that use it on white light when carrying the scope parts out. Again, when starting out, don't get obsessive about dark adaption, you are looking at mostly bright objects to start, not mag 15 galaxies!!
Eyepieces. This comes with a 25mm and a 10mm I believe. If they are the same that came with my old Saxon scope, the 25mm is not bad and you will use it a lot! The 10mm basically use on planets (Jupiter and Saturn mainly) and thats about it. My advice is don't spend hard earned on EPs until you know what you want.
Inertia mentioned the GSO SuperView ep's. I have both the 15 and 30mm versions as lightweight options for my 8" travel dob and the 15 is a little ripper for a small scope. The 30 is also OK but does exhibit some pretty severe aberrations near the edge of the field, but for the $$$ not bad options. Your statement " its no good buying the cheaper ones" is not strictly correct, wise choosing and good research can save a considerable amount of money. Unfortunately money usually does buy quality, but there are some better budget options out there.
The other accessories I would look at a re a folding table, as light as possible so it is not a hassle carrying to the field and a chair. Oh and a good chart. I am not a fan of planetarium programs, tried a few of them and found paper charts always work. Don't have to worry about the device getting wet, running out of power, being dropped etc. Best options are
Least expensive: http://www.bintel.com.au/Accessories...oductview.aspx
Help you locate all the Messiers, many brighter DSOs, work out the constellations etc.
Middle range:
Sky Atlas 2000 http://www.bintel.com.au/Accessories...oductview.aspx
There are several version ranging from $49 to $149 I think. Excellent charts, easy to read and well designed
Top Range
Uranometria 2000 http://www.bintel.com.au/Accessories...oductview.aspx
Not really a beginners, and I found I needed a cheaper chart as well as these to help me get started, but excellent value.
A book worth considering to get you started is http://www.bintel.com.au/Accessories...oductview.aspx
It is not cheap, but you can shop around. All the objects are easy to see in an 8", almost all will be visible from where you are and and observing them is a great start to an astro journey.
Thanks Malcolm (Hope you get well )and everyone for your help! , I now have a baby 8" Saxon Hubble! It seems huge! 4 inches under my chin!
In seemingly excellent condition, including the plossl 25 mm -10 mm and a 2 x barlow!
Just got, back from the exhausting 450k round trip including getting lost! My GPS phone going into silence on the last leg and only 5 mins of power left to ring the seller 2x for help directions!
With hardly much sleep, leaving at 7am and home here at 4pm.
I now know what it must be like to have a child sleeping in the back seat, but it was safely cradled with every cushion pillow and doona I own...
Large cumulonimbus clouds have formed over the valley and Northern NSW?How strange?
Hmm but I'm going to bed, maybe I will catch Jupiter before sunrise?
(The mirror looked fine but the reflection has aged a bit!)
Will report soon on my first adventures in deep fuzzy space
Cheers and thanks again.
Edit, just admiring the edifice before bed, it starts lightly raining with hail? But no storm?
Last edited by creeksky; 10-01-2015 at 04:59 PM.
Reason: weather
Your adventure has just begun Pete & now your scope has a story :-)
I have scopes from 4" to 10" have had up to 18" Dob, Go-To SCT & they all have their place. In the end the scope you can use easily is the one you will want. Your off to a great start, enjoy the journey !
Your adventure has just begun Pete & now your scope has a story :-)
I have scopes from 4" to 10" have had up to 18" Dob, Go-To SCT & they all have their place. In the end the scope you can use easily is the one you will want. Your off to a great start, enjoy the journey !
Thanks Ian. I have made my first observatory site, Used my brush cutter-anyone for a Star Party?
Unfortunatley Venusian skys have enveloped the valley! You are all invited! Clear skies and no street lights for 24ks, if the weather is just cloudy,we can have outdoor movies with my projector.
http://i62.tinypic.com/16kq0kg.jpg view to the East ,opening of the valley.
Solar system chart, tribute to Barx1963 (until I get real charts) and red solar torch needs cellophane -3 layers.
Last edited by creeksky; 11-01-2015 at 10:41 PM.
Reason: added text and pics, cardinal correction.
Should the swivel base be very loose? Mines seem tight?
I have just today realized I'm going to have to move this every few seconds?
In a quick jerk action?
To keep the object in view.
I had a flashback to seeing people using DOBs (maybe in a movie?) and it looked manic. I guess it becomes automatic,I'm not sure I can do it..
Slacken off the turntable centre nut until it moves smoothly.
Dobs are best for low powers. A 2" 30 or 42mm Superview EP
will give great widish field views, and reduce the frequency of nudgings.
raymo
Slacken off the turntable centre nut until it moves smoothly.
Dobs are best for low powers. A 2" 30 or 42mm Superview EP
will give great widish field views, and reduce the frequency of nudgings.
raymo
There is one nut on top and one underneath, from what I can see I need 2 shifting spanners.
One to hold a nut while I turn the other -correct?
Slacken off the turntable centre nut until it moves smoothly. Dobs are best for low powers. A 2" 30 or 42mm Superview EP
will give great widish field views, and reduce the frequency of nudgings.
raymo
So viewing Saturn and Jupiter in wide field views will show detail?
Yes, you will probably only need to slacken it off a tiny bit.
You will see the two cloud belts and some of the moons of Jupiter
at any magnification. [only as specks like stars at low powers]. At higher powers the moons become tiny discs. [ black when passing in front of the planet].You won't see detail on Saturn at low power, and not much at higher power. Saturn is fairly bland.
You should see the Cassini division in it's rings at moderate power.
Non go to Dobs are not ideal for planetary use, as high powers are normally used, and it is hard to keep a planet in view at high power.
raymo
Should the swivel base be very loose? Mines seem tight?
I have just today realized I'm going to have to move this every few seconds?
In a quick jerk action?
To keep the object in view.
I had a flashback to seeing people using DOBs (maybe in a movie?) and it looked manic. I guess it becomes automatic,I'm not sure I can do it..
Should I loosen the base?
Loosening the base is something you do until you feel comfortable. If you loosen it too much it can swing around with any wind, so play around until it feels comfortable.
Manually moving a scope comes very easily after a while. The reversed image does take a little getting used to but after a while you just don't notice it any more. At high powers, you will find yourself moving the scope a bit. But if you think about it a standard 8" dob has a focal length of 1200mm. So a 10mm EP with a 50deg AFOV (apparent field) will give 1200/10 = 120x so 50deg/120 = 25' wide TFOV (true field) so an object moving through the sky at 15' per minute (which is how fast objects on the celestial equator move) will take 1.66 minutes to cross the field of the eyepiece. So you probably only give it a nudge every 20-30 seconds or so.
With a 25mm plossl, an object takes over 4 minutes to move across the field. I find the trick with high power is to work out which direction in the field the object is moving, and setup the view so the object moves through the centre of the field. That gives time for any vibrations in the scope to die down and for my eye to relax and start soaking in details.
Loosening the base is something you do until you feel comfortable. If you loosen it too much it can swing around with any wind, so play around until it feels comfortable.
Manually moving a scope comes very easily after a while. The reversed image does take a little getting used to but after a while you just don't notice it any more. At high powers, you will find yourself moving the scope a bit. But if you think about it a standard 8" dob has a focal length of 1200mm. So a 10mm EP with a 50deg AFOV (apparent field) will give 1200/10 = 120x so 50deg/120 = 25' wide TFOV (true field) so an object moving through the sky at 15' per minute (which is how fast objects on the celestial equator move) will take 1.66 minutes to cross the field of the eyepiece. So you probably only give it a nudge every 20-30 seconds or so.
With a 25mm plossl, an object takes over 4 minutes to move across the field. I find the trick with high power is to work out which direction in the field the object is moving, and setup the view so the object moves through the centre of the field. That gives time for any vibrations in the scope to die down and for my eye to relax and start soaking in details.
Cheers
Malcolm
Ok thanks, so If I am nudging it away or toward me, won't I have to move my seat and move away from the EP each time?
From the test set up I found my chair will not be high enough and I would be leaning slightly twisted to see into the EP,I was going to use a computer chair which if I put it on a pallett to gain height will probaly roll off.
Trying it down with straps, would be awkward if I decide to look in a new direction.
Guess I will have to experiment if the clouds ever go away!
Facing a similar conundrum myself and not wanting to immediately spend $180 on a Bintel Chair, I decided to build a Denver Chair.. I had some old formply and an 8m piece of 2x4 under the house so used that instead of buying new wood and also had some automotive fuel tubing.. I'm not going to use the stair tread as it's apparently not required.. we'll see.
It's cost about $35 in various materials, mainly bolts and nuts and screws, a decent 3in hinge and a 32mm x 3mm x1m aluminium strip.
Without having the materials at home it can get to about half the cost of a Bintel Chair not including your own labour so scrounge around is my advice! It's good fun building stuff anyway!
A cheap alternative for home use is a gas filled height adjustable stool.
About $35 from the "cheap" shops.
Seems to cover the height range for me, and no set up.
Not so good for travelling to remote sites (I have a Bintell chair for that).
Facing a similar conundrum myself and not wanting to immediately spend $180 on a Bintel Chair, I decided to build a Denver Chair.. I had some old formply and an 8m piece of 2x4 under the house so used that instead of buying new wood and also had some automotive fuel tubing.. I'm not going to use the stair tread as it's apparently not required.. we'll see.
It's cost about $35 in various materials, mainly bolts and nuts and screws, a decent 3in hinge and a 32mm x 3mm x1m aluminium strip.
Without having the materials at home it can get to about half the cost of a Bintel Chair not including your own labour so scrounge around is my advice! It's good fun building stuff anyway!
Good ideas Allan and Inertia,though I have never seen the "cheap chair"?
I guess have to look in furniture stores?
Building one looks like fun, but I don't understand how the chair slips up and down and stays in position,Is it like a car seat belt?
Searching the forums and Google someone found a guitar chair-here http://www.swamp.net.au/guitar-stool...fhGxoCdHLw_wcB
Though there seems no record of how practical it was?
I could build part of that Denver chair,but don't know how to bevel,and If I did make one it would probably slip to the ground with my mechanical skills
By "cheap" shop I refer to the Reject Shop, or similar.
Don't go to a furniture shop they will charge 3 times the price for the same object.
Aldi sometimes has them also.
no need to jump off to adjust, just pull the lever and adjust in situ.
.
