How Dim a star can you guide on? Or what Guide Cams do folk recommend?

g__day (Matthew) · #1 01-09-2008, 09:32 PM

I think I am rapidly outgrowing my Meade DSI. Its hard to use on DIM stars - hard to focus and under PHD easily looses the star - even if I set the light gathering duration all the way up to 10 seconds.

In increasing order of expense - what guide cams would folk recommend and where is the sweet spot in folks opinion (how much to spend before it will work (on PHD or MaximDL on faint stars too)!

Many thanks,

Matthew

gbeal · #2 02-09-2008, 10:07 AM

QHY5 Matthew, I use mine with a 65mmx500mm guide-scope, and while I have adjustable rings, I rarely if at all use the ability to "offset it.
Gama will be able to supply one, and with mine my "normal" exposure time is 2 seconds. Setup with Maxim DL is 5 minutes.
Gary

vash (Ashley) · #3 02-09-2008, 10:29 AM

I find my dsi 2 has been easy to find stars anywhere in the sky, my normal exposure is around 0.2 seconds around star populated area's, in fainter areas around .5 seconds is fine, I'm using a Skywather ed80 at f 7.5, I went from an lpi which found barely anything straight to this and have never missed the little thing.

madwayne (Wayne) · #4 02-09-2008, 01:04 PM

I have to back Gary up on his recommendation of the QHY5. If you do go down the QHY5 path may I suggest you get the mono and not the colour. I followed Theo's advice and got the mono and I never have troubles picking up a guide star with my ED80 using PHD. Similar to Gary I use between 2 and 3 seconds as my exposure time on the guider.

All the best.

Terry B · #5 02-09-2008, 01:59 PM

I like my QHY5 guider. I rarely use any exposure longer than 0.8 sec using guidemaster through my 127mm APO (yes it is doubling as my guidescope)

gbeal · #6 02-09-2008, 02:38 PM

Further to Waynes comment, mine is the mono as well.
Gary

g__day (Matthew) · #7 02-09-2008, 11:21 PM

Agree get a mono guide camera definitely (far more sensitive without a Bayer mask)

On the QHY5 as a guider - a question on its compatability with current releases of PHD. The current release (V1.9.0) doesn't have this CCD natively listed, and on their forums I see folk saying manipulate Windows DLLs when every you install a new version of PHD and for G11 owners switch the 4 1K resistors to a single 51 Ohm resistor etc - is it ready to go out of the box - or is alot of fiddling need to get this to work properly?

Alternatively the DMK 21 Mono USB is $460 camera that is only .3 Mega Pixels (Q/E not specified)

Orion Starshoot Autoguider is $370 for a 1.3 Mega Pixel CCD - Q/E not specified

AlexN · #8 03-09-2008, 01:54 AM

my DBK31 picks up alot of stars in a 2-5 sec exposure... 1/3" .8mp
the 1/3" chip provides a nice large field of view... however these cameras are kind of expensive as a guide cam only.. $669

gbeal · #9 03-09-2008, 06:15 AM

Mine was plug and play Matthew, not mucking about. It does get listed as a Q Guider though in the PHD menu. No problems whatsoever with Maxim.

vash (Ashley) · #10 03-09-2008, 10:11 AM

Should also add mines a DSI 2 Pro mono version.

Tandum (Robin) · #11 03-09-2008, 10:44 PM

Just tried installing my qhy5 on vista64 and it failed in a screaming heap, however PHD 1.9 installed on XP and picked up the qhy5 just fine without copying custom dll's as was required before.

Contact Gamma about the resistor question.

Gama · #12 04-09-2008, 01:38 AM

Vista 64, forget it !. Most of the I/O controlled devices dont work on Vista64 with 32bit drivers, 30 % of programs also dont like Vista64.
Vista 64 is a whole new ball game, and there is limitations on what microsoft want you to load as a driver.
Not only do you need to pay a yearly fee to recieve a digital signiture (Vista64 doesnt even let you load it, as it blocks all non approved signatures), but also the amount of time you need to redo the whole program and drivers.
However, Vista 32 works fine, but there may be 64 bit version later.

Also as some have mentioned, you can select other models in PHD that are the same cameras, like the Magzero 5, and Qguider etc.

Theo.

Babalyon 5 · #13 04-09-2008, 09:13 AM

Quote:

Originally Posted by vash

I find my dsi 2 has been easy to find stars anywhere in the sky, my normal exposure is around 0.2 seconds around star populated area's, in fainter areas around .5 seconds is fine, I'm using a Skywather ed80 at f 7.5, I went from an lpi which found barely anything straight to this and have never missed the little thing.

I similarly use a DSI Pro 2, but to image with(great sensitivity) and a DSI 1 Colour to guide with, no problems. General guide exposure time is 1 second through an Orion ST 80mm. I use Envisage, PHD or Maxim to guide with, no problems here either.

Babalyon 5 · #14 04-09-2008, 09:18 AM

Another thought is do you have your guide scope in adjustable rings so you can recenter it on a brighter star over a bit or towards the edge of your field if there isn't a bright enough star in your imaging field?

AlexN · #15 04-09-2008, 09:44 AM

most people do...

RB (Andrew) · #16 04-09-2008, 09:53 AM

Just a question, I seem to remember reading that the QHY5 is the same/similar to the Orion Starshoot Autoguider, is this correct?

g__day (Matthew) · #17 04-09-2008, 10:03 AM

I find I have to guide using an off axis guider to avoid star trails - I presume this is due to slight mirror shift on the main SCT rather than any differential flexure on my other two OTAs. This places high sensitivity demands on the guide CCD and whilst the Meade DSI is up to it for bright stars - imaging say the Helix nebulae on a new moon at 10 second intervals barely lets me lock on to a guide star with careful selection.

So I figured a CCD with more sensitivity would be a boon!

madtuna (Steve) · #18 04-09-2008, 12:10 PM

Quote:

Originally Posted by RB

Just a question, I seem to remember reading that the QHY5 is the same/similar to the Orion Starshoot Autoguider, is this correct?

I understand they are the same camera Andrew just running different firmware. I have the Orion Star Shoot, havent had a good run through yet but it seems very user friendly

RB (Andrew) · #19 04-09-2008, 12:39 PM

Quote:

Originally Posted by madtuna

I understand they are the same camera Andrew just running different firmware. I have the Orion Star Shoot, havent had a good run through yet but it seems very user friendly

Cheers Steve

I just picked one up too so hoping it will work well with PHD 1.9 or the software that came with it, which I believe is also PHD.

Gama · #20 04-09-2008, 06:39 PM

Quote:

Originally Posted by madtuna

I understand they are the same camera Andrew just running different firmware. I have the Orion Star Shoot, havent had a good run through yet but it seems very user friendly

Your correct, it does have different firmware due to licensing reasons. Software and drivers are limited for the Orion model, but hopefully this will change in the future. Check with www.astrosoft.be for the latest on all the drivers for them.

Theo.