Help : Can You find any Data ?

[Mr TamiyaCowboy]

single 25s sub. 

taken with ST80 mounted prime to a canon 350D.

400mm @ F5.0 , ISO1600 @ 25s

Target destination : Leo Triplet

Mount: merlin goto ALT - AZ

brightest star alignment ( set from park(north'ish)

so 400mm should give atleast some hint, aquired target M66

slewed to M65 then back to M66 ( very short skip to both )

set camera and fired off, 27 shots this is the only frame with clear round stars

the rest are streaks.

image has been converted from CR2 into jpg as my tiff file works out to be 45mb ( raw was 6.5mb).

Jpg is 6.5mb, and i cannot find any data not even a hint of anything.

i also added a dark just in case it would be required. 

[Leveye]

There are many factors why only one came out. I toss quite a few away.Usually 15 out of 30. You must balance and polar align the mount extremely well to get great results. Just keep at it.

[Mr TamiyaCowboy]

i cannot polar align a ALT-AZ. the merlin has instructions to ...... 

set mount with mount arm to the right hand side, set scope pointing north

and level. ( this north and level is also PARK/Home).

i have an idea why the single frame is only one, soon as i had a target lock

i flipped to siderail tracking mode. on this image i had canceled siderail

and just went direct to target hit shutter and left it running.

All the rest the mount was siderail tracking. 

thats what puzzled me, 400mm non tracked should start showing trails very quick.

but the image above shows nice rounded stars non tracked. ( goto target slam shutter and pray).

[jarlaxle2k5]

I did a little research about your mount and i have found this:

MERLIN SYNSCAN™ AZ GOTO COMPUTERISED TABLE-TOP ALT-AZIMUTH MOUNT

Main Features:

SynScan™ Database: Total 42,900+ Objects, including Complete M, NGC, IC & SAO Catalogues 
Alignment Method: Two-star or Brightest star alignment 
Pointing Accuracy Enhancement (PAE) feature 
Unknown Object Indentification feature 
Pointing Accuracy up to 10 arc min 
Tracking Rates: Sidereal, Lunar, Solar 
Slewing Speeds: 1.0x, 2.0x, 16x, 32x, 64x, 128x, 400x, 500x, 600x, 800x 
Tracking Mode: Dual Axis Tracking 
Quiet Operation 
Motor Type & Resolution: DC Servo Motors. Resolution 0.8923 arc sec or 1,452,425 steps/rev 
PC Compatible: can be used with popular Planetarium Software. 
SynScan Handset Firmware upgradeable via the Internet 
Height 35cm 
Weight 2.9kg 
Power Requirement: 12v DC Power Supply (Tip Positive) or AA Batteries (not supplied). Sky-Watcher 7Ah or 17Ah Power Tank Recommended

So if i am correct that mount does tracking and for 25sec exposure it is correct that you don't see any trail.

You should start to see star trail when you push above 30sec.

That's what i have experienced with my scope on alt-az synscan goto mount.

[Leveye]

It you don't balance and polar align the mount perfect you're never going to get anything much without streaks. You should be autoguiding with a CCD and a program such as PHD. Check it.

[glowingturnip]

i've not used an alt-az synscan mount, but would have thought that for sidereal tracking it would still need a good idea of where north is so that it sidereal tracks in the right direction (otherwise it could go any direction really).  So I'd suspect you need to set the mount up with a good stab at north, and then at least a 2-star align ?

you could upload the above image to the astrometry group on flickr to see if you were on target or not

[Mr TamiyaCowboy]

i know lots factor in about star trails. 

How does someone POLAR ALIGN an alt-az mount ? as these SW instructions must be wrong,

if you have to polar align the mount. ( i aligned mount via compass, then via a 3axis digital compass, and via the sun at noon)

all three alignments are bang on. just shy magnetic north give or take.

The image, if the goto centered the object, namely either M65 - M66 there should be a large'ish Core atleast.

( theres no core in this image) Second, does this image resemble the leo triplet area ( ie star layout, etc etc)

I would have expected something with a fast scope long exposure and somewhere in frame.

third question would be, if thats not Leo, where did the goto send the scope to and what target is really in the field of view. 

(alignment stars used in mount : procyon  and zosma).

[dph1nm]

The triplet is about 1 deg north of your image - so you just missed it!

NigelM

[Mr TamiyaCowboy]

The triplet is about 1 deg north of your image - so you just missed it!

NigelM

thank you NigelM your a star ( beg the pun lol) 

looks like the mount, has shifted a tad in AZ , will need to go and hammer the error adjustment somewhat.

and also refine the whole scope seat arrangement. 

thank you again, 

Paul

[dph1nm]

I would recommend you try and point at one of the bright stars in Leo first (a few secs exposure will suffice), to test the pointing.  I have an Nexstar alt-az mount  and they aren't always the greatest for pointing so it pays to do a quick check nearby first.

NigelM

[Cornelius Varley]

It you don't balance and polar align the mount perfect you're never going to get anything much without streaks. You should be autoguiding with a CCD and a program such as PHD. Check it.

The Merlin is an alt azimuth mount. By definition it cannot be polar aligned, nor can it be autoguided. The mount should be capable of at least 25 second exposures however before trailing becomes apparent.

[Mr TamiyaCowboy]

The Merlin is an alt azimuth mount. By definition it cannot be polar aligned, nor can it be autoguided. The mount should be capable of at least 25 second exposures however before trailing becomes apparent.

thank you peter, yeah the alt - az is a funny thing,

but very handy, i also use the merlin with pappywizard and turn it into a

panorama photography head so it has a dual function  to me. 

i was also thinking the same for shorter focals ? say a 50mm would allow somewhat longer exposure ?

and WOW, that dark is bad, never noticed this many dead/hot pixels before,

maybe the camera is on her last legs i know i have put through a couple thousand shots

or more, so the shutter count must be going on 100 thou maybe even more.

daylight images still look great for the tech of the day.