Is this telescope worth the money ..please

[UK1 (Rob)]

Bintel BT302-B 12" Dobsonian
300mm x 1500mm (f/5)
First Grade Dobsonian
Price: $899.00

also any good for taking photos of Planets ?

[Allan_L (Allan)]

Generally, a 12 inch Dobsonian is a great telescope.
At that price, I assume you are talking brand new from a dealer.
And yes that is a good price.

But,
A 12 inch dobsonian is a large telescope and quite heavy.
And awkward to move around any distance.

You need to consider if you will be taking it to dark remote sites and if it will fit in your car. Usual method is laying across rear seat.

You might consider a collapsible dobsonian, which are more expensive, but easier to transport.

As far as astro photgraphy is concerned, a DOB is usually not the best for long exposures.
But for bright planets and moon with short exposures they have been used by others with some success. But they are primarily an easy set up visual observing scope. (IMHO From my experience).

[UK1 (Rob)]

thanks for the reply
I all ready have a 8" on an EQ6 pro go to mount and an ED80 thinking of selling them both with eye pieces and filters ( not sure how much they are worth ) as there is no one up here that can help a newbie
thanks again

[Visionoz (Bill)]

Originally Posted by UK1

thanks for the reply
I all ready have a 8" on an EQ6 pro go to mount and an ED80 thinking of selling them both with eye pieces and filters ( not sure how much they are worth ) as there is no one up here that can help a newbie
thanks again

Hi Rob

Was just wondering as to what difficulties you're experiencing atm and what kind of help do you need?

Cheers
Bill

[batema (Mark)]

Good scope, good price and when we bought our GSO 12 " DOB we went galaxy searching on the first night and were blown away at both quantity visible 15 at least and how goos the image was. Big scope but great fun.

[UK1 (Rob)]

Bill
I just need someone to help me get started just going over set ups and drift align all the newbie things cant seem to find anyone doing astronomy up this way. was hoping to do some photography have all the equiptment.
no clubs, or any people I can get into contact either.
never mind just give it up and sell it all.

[raymo]

Hi UK1, Please don't give up this great hobby; we can't afford to lose you.
I have moved a lot over the years, and when I moved somewhere small,
or a long way from the nearest club, I went to the local paper and asked them if they would do a short feature on me and my scope. They came to
my place, took a pic of me with my 10" dob. They asked anyone interested to call me. In nearly all cases I got between 6 and 12 people
call me, some of whom had scopes. Give it a try, local papers are always
looking for local interest features.
Regarding the 12" dob, nothing I can add to the other replies except
to say that my preference is a 10", which I think is the best compromise
betwen aperture and portability.
Personally, I would stick with the set up you already have. There are numerous tutorial videos on the net. I think you might find having to constantly nudge the dob a nuisance, after using your EQ6. The 8" gives
pretty good views, and even if only roughly polar aligned will allow long enough exposures for you to get half decent images of some types of
objects such as globular clusters and some of the brighter nebulae.
The only suitable target for a dob is the moon. The planets are best
imaged by stacking many frames [usually video], and of course with a dob
the planet will move during the filming of the video. Single exposures
of the planets are rarely very good. Even moon images usually need
computer processing to get the best out of them.
I hope this helped
raymo

[batema (Mark)]

Hi again UK1. What equipment do you have including mount, scope and programs. Do not give up as this hobby is a fantastic and rewarding adventure. It is a steep learning curve but with this forum and others you should be able to get going.

Mark

[Visionoz (Bill)]

Originally Posted by UK1

Bill
I just need someone to help me get started just going over set ups and drift align all the newbie things cant seem to find anyone doing astronomy up this way. was hoping to do some photography have all the equiptment.
no clubs, or any people I can get into contact either.
never mind just give it up and sell it all.

Hey Rob

Stating the obvious with what others have said - ie don't give up yet mate! You seemed to have got the gear to do all that you want and it's a shame if you give it all up now especially with the monetary losses you'd cop as well since I noticed of late that things in the IIS Classifieds are moving veeeeery slooooowly too

Just to let you know I do have a lot of imaging gear and wish now that I could get rid of half of what I own because I don't use any of it but I started right off wanting to do the astro-imaging stuff since 2009 and I spent many mozzie-bitten nights for the first 3 weeks figuring out how to do the damned polar drift align gig and finally it all twigged for me especially after I went to this website: http://www.petesastrophotography.com/guidingsim.html and I discovered that I actually had the thing down pat BUT stupid me, I did not turn on sidereal tracking on the mount and no wonder the damned star that I was aligning on kept on zoooooming past my reticule EP!!

Could you tell me if you do know how to set up the mount in rough alignment to the SCP (to true South)? Perhaps you should not need to answer this here if you don't want to, just PM me and we can take this forward off-line if you wish and let's see if we can get you going

Otherwise if you are coming to Perth for a visit anytime (especially aro new moon time would be better as we can do some actual imaging) I would be more than willing to spend the hours with you with my similar gear (EQ6 Pro mount that I could loan you the use of - you just need to bring your 80mm OTA/camera) and show you the works either at my remote obsy or at Tammin (ASWA's Dark Sky site and I'm a sitting Councillor as the Site Adimiinistrator for Tammin) and I'm sure you'll be grinning from ear-to-ear after!!

Let's see how you'd like to go forward - over to you Rob

HTH
Cheers
Bill

[Kal (Andrew)]

If you want practice drift aligning use the simulator at this page. When you can practice it on a pc it makes it simpler to do out in the field

http://www.petesastrophotography.com/guidingsim.html

[raymo]

Hi Kal,
Thanks for the simulator, but as it seems to have no
instructions, I just did what I do at my scope, and try as I might
I could not stop the star drifting in one direction or another. I don't
have any problem drift aligning my scope; I just thought that I would
have a go at the sim to see how good it was. Perhaps I'm doing
something wrong.
raymo

[OzEclipse (Joe Cali)]

I suspect one of the main problems you face is that your EQ6 mount cannot easily be set up for Cairns 17 deg latitude. The EQ6 mount has a 25 deg latitude limit before collisions between the counterweight with the tripod become an issue.

The way some get around it is to lower one leg but juggling stability, balance, and alignment with such an out of level mount will be very confusing and difficult for a beginner.

I don't own an EQ6. In the first instance, could one of our EQ6 owning IIS members reading this check and confirm whether the mount can physically be tilted to 17 degrees without tripod tilt. If so then UKbob could add an extension pier to avoid the tripod collision. If 25 degrees is the hardware limit then some other engineering solution might be in order such as an extension pier with an added 10-15 degree wedge.

There are IIS members from Cairns and surrounds. I don't know what their telescope experience is like.

cyclone from Mareeba.

Also Ian McClean, gaa_ian (Ian) NT Stargazer from Darwin may have some experience to with the problems of mounts at tropical latitudes.


There is also plenty of support available here though none of us can help you directly..

Cheers
Joe

[Kal (Andrew)]

Hi raymo,

Here are some instructions:

Once the simulator loads, click on the startup screen to begin. Immediately you may see stars moving across the eyepiece field of view. Do not worry, they will loop around so you can track one when you are ready.
The first thing you need to do is turn the POWER on. Click on the button in the lower LEFT corner labeled "Power". This will start the mount tracking in Right Ascension (RA).
This simulated equatorial mount has a random polar alignment - The mount's polar axis is pointing towards the celestial pole but is not very accurate. You will get a lot of declination drift, enough to ruin most astro photos. This is what you will now correct!
Periodic Error Correction (PEC) is NOT turned on so you may see some small RA drift. If your own equipment does not have PEC, you should leave the PEC off on this simulator too. To rturn on PEC, click the tiny word "PEC" on the hand controller.
This simulator starts off with the telescope pointing at the intersection of the Celestial equator and Meridian, which is the best place to start the drift alignment procedure. Later you will be able to swing the scope over to the Eastern sky to correct for Altitude misalignment.
Press the #5 or #6 button on the hand controller to switch the slew speed to a fairly fast speed. You can play with the hand controller's arrows to get a feel for how the scope responds when slewing up/down and left/right.
Using the LEFT, RIGHT, UP and DOWN slew buttons move the scope to locate a suitable guide star. You need to quickly line up the illuminated guiding reticle lines with the EAST/WEST axis of your scope. To rotate the eyepiece correctly, use the LEFT or RIGHT arrows on the telescope control box. Quickly move the star to the left and right using the left and right slew buttons and then ROTATE the eyepiece until guiderstar moves along one of the lines of the eyepiece. The star may be drifting up or down (north/south) but this can be ignored for now.
Using a slower SLEW speed, place the guidestar along one of the reticle lines in the center box. If you select slew speed 1, this is called GUIDE SPEED and it simply doubles the normal RA tracking rate when you want to move forward, and simply STOPS it for reverse. I suggest you use a fster speed to get close to center, then switch to a slower speed when ready to begin making corrections.
- You will notice that the guidestar is probably moving off your chosen line. Any back and forth movement along the RA loine is due to periodic error of your RA drive. This will show up as movement in the East or West (Right Ascension-RA) direction only. You may also note a lot of drift in the North or South (Declination-DEC) due to polar misalignment.
- You may correct any RA movement (Left/Right) to keep the star centered, but do NOT correct any Declination drift. You must however NOTE which way any DEC drift is.. either Up or Down.
AZIMUTH IS MAD!
Now it's time to CORRECT any Polar misalignment in AZIMUTH (East/West). This is because your MOUNT's POLAR AXIS may be pointing too far EAST or too far WEST of the true celestial pole. On your own mount you must know how to adjust the Azimuth of your mount, and on most mounts it's a large screw that slowly rotates the mount to the East or West. On the SIMULATOR, you simply press the EAST or WEST buttons on the TELESCOPE control box next to the label AZIMUTH. These move the mount in small amounts to the East or West - when looking north. That is, the north end of the scope will move slightly to the left or right, with WEST being to the LEFT and EAST being to the right. This may look backwards in your eyepiece, since the scope is pointing South.
While watching declination (DEC) drift only, if the guidestar moves UP, rotate the mount's AZIMUTH so that the guidestar moves to the RIGHT in your eyepiece. If the guidestar moves DOWN, rotate the azimuth so that the star moves LEFT. The reason you make these moves is described in the TUTORIAL. DO NOT use the slew buttons on the hand controller to do this. Use the AZIMUTH buttons on the telescope control box. On your own mount, you must physically rotate the mount as described above.
- The faster the guidestar drifts up or down, the more azimuth corrections you must make. If the guidestar drifts quickly, your mount is much further away from the celestial pole, and will need to be moved a lot further.. so far in fact that the guidestar will move right out of the field of view! No worry.. you can always grab another star to finish the alignment process.
- After you make the mount correction, quickly re-center the guidestar with the HAND SLEW CONTROLS. Again, you can use any star in the area if you can not find your original guidestar.
- Repeat these steps by watching the guidestar's movement in DEC and adjusting the mount in AZIMUTH until you no longer see any drift for several minutes. For very long astrophotography, you should not see any drift for 5 minutes. Once the DEC drift has stopped, you can go on to the next section to correc the Altitude.
ALTITUDE IS EASY!
Now it's time to correct any North or South) misalignment. This is ALTITUDE misalignment. Your mount may be too far ABOVE or BELOW the celestial pole, too far North or too far South.
On your own scope you must now rotate the mount's RA axis and move to the EASTERN or WESTERN horizon. DO NOT move the mount azimuth or altitude position... just the scope in RA. On the SIMULATOR, press the EASTERN HORIZON button and press "YES" to slew to the correct position.
Again, be sure the eyepiece is correctly oriented so that any East or West movement in RA will cause a star to move along the reticle lines. When done, choose a bright guidestar and center it again just as you did before.
Watch for any DEC drift again. Remember, you can adjust the scope in RA (East or West) but do not adjust for any declination drift.. just simply watch for it.
If the guidestar drifts UP, adjust the mount's altitude to LOWER the star. If the guidestar drifts DOWN, adjust the mount to RAISE the guidestar. You are just reversing the direction the guidestar is moving. To RAISE or LOWER the simulator's mount, press the North or South buttons on the Telescope control box (not the hand controller). The North button will RAISE the mount. The South button will LOWER it.
- Keep raising or lowering the mount until you no longer see any DECLINATION drift. Recenter the guidestar after each movement just like before.
Repeat the whole process by going back to the celestial equator and meridian and checking the AZIMUTH again. This method will allow you to get VERY HIGH precision in Polar Alignment with your mount, suitable for very long astrophotography exposures. If you have to make a large change in Azimuth, go back and re-check the Altitude again too.
After you feel you have achieved accurate polar alignment, press the small round button in the UPPER LEFT corner of the RIGHT SIDE control box. This will turn on the POLAR VIEW and show you the location of the Celestial Pole as a blue circle and cross-hair. If you have done your job well.. the pole will be centered in the red cross hairs of the mount's Polar Axis.
So, in review:
To correct AZIMUTH.. watch a star near the celestial equator and meridian. If it moves UP, rotate the MOUNT so the star moves to the RIGHT in the eyepiece. If the star drifts DOWN, rotate the MOUNT so the star moves to the LEFT.
To correct for ALTITUDE, watch a about 15 to 20 degrees above the Eastern Horizon. If it drifts UP, move the mount so the star goes DOWN. If the star drifts DOWN, move it up!

[raymo]

Thanks very much for the comprehensive sim instructions Andrew.
raymo

[tlgerdes (Trevor)]

Geez you make it sound complicated!

ftp://www.sarcasmogerdes.com/downloa...HD-graphs.pptx