Merlin66

My Genesis is serial # 1007.

 It came with the TV Systems mount.

1988 was the start of the Genesis production....so Mid 1988 manufacture?

P28 shows the LX5.

Hmmm,

Looks like an old LX5 SCT....corrector plate and secondary missing.

Difficult to find suitable replacements...

https://skywatch.brainiac.com/used/used_sct.pdf

Vin,

OK I now see you've used a DSLR (?) for imaging.....

Unable to get a good stack from AS3! - it shows multiple artifacts.....

Vin,

Just downloading your files....

PNG is not a good format to start with - TiFF or Fits would be better.

Normally you would use a fast frame camera and record in AVI or SER, then process the video through AS3! etc.

Keep you posted.

Good to see another Genesis still working hard................

Note of caution....

I have a set of the Baader delrin spacers bought many years ago and found the inner diameter would not fit over the t thread!!! In the end I had to cut them to get them to fit.

I note this has also been reported by other users in the past. Don't know if Baader have changed their tooling to address this issue.

CWL = central wavelength

Have a good night's sleep!

Louise,

Hmmm, shouldn't be "dramatically" different......

Remember you're using achromat lenses....the focus will vary with wavelength.

That's why you should refocus (using the reference lamp) on an emission line close to your required CWL, to get best FWHM every time.

Louise,

Yes looking better!

Still some dust (?) near the top of the slit... 

Could be you should use a diffuser (sheet of paper) between the CFL lamp and the inlet.

I'd run with what you have and work towards getting a star spectrum.

Onwards and Upwards.

The in-built filters (colour correction and AntiAlias/ dust shake) in the commercial cameras are there to give an "acceptable" colour balanced image to the eye. This is what the majority of users pay the money for.

These filters modify the output from the CMOS chip to achieve this; the response to the red part of the CMOS chip spectrum is reduced by about 40% to give "normal daytime colour rendering to the average user"

When the camera is "modded" the colour correction filter is removed, thereby allowing a 40% improvement in the red response - very useful to astronomers trying to record Ha in nebulae.

This can't be done by adding extra filters up front.

HTH

Using a C11 at f10 and a small FOV reflective slit plate (for spectroscopy) which is only 8.6 x 13.1 arcmin, I end up using a 60mm x 220mm fl eFinder (ol' DMK51 camera) for the occasional plate solving.

Works well for me.

If you look carefully at the slit image you see it has a sort of twisted appearance....the bottom section shows it a bit clearer...

This usually is seen when the slit gap doesn't align with the grating grooves. If the slit plate is not 100% registering to bring the slit alignment this could result. Just try a slight rotation of the disk see if it improves.

(Imagine the grating is sitting with the "grooves" in the grating surface sitting vertically.....the the slit gap should also be arranged so it's height is sitting vertical and parallel to the grating grooves...)

EDIT: The last 30 sec exposure shows what looks like dust on the slit ( top three dark areas) the illumination is not "regular" along the slit. Try similar exposures but with a slightly wider slit gap 30 micron or so.

Louise,

Looks like the slit is not exactly aligned with the grating grooves...

The image seems to have been under exposed and stretched - what did the "normal" exposure show?

 You should be able to get an image close to Paul's example.....

From my understanding the slit illuminator illuminates the rear of the slit plate and should have no impact on the quality of the zero order image??????

Louise, you could be over exposing the zero image. Looking at your CFL spectral image you can see the top and bottom "edges" are not tight and clear. This could due to uneven illumination ( from the reference lamp positioning) or vignetting within the optical arrangement.

If you can image the double stars, then Florent Losse's Reduc program is the one to use.

Email him for a copy. florent_losse@yahoo.fr

http://astrosurf.com/hfosaf/

for use with guide cameras which have no ST-4 port.......

Using a guide scope, prefocussed on infinity,  positioned behind the collimator. The slit gap should be in focus and a clear narrow gap.

Louise,

Collimation of the spectrograph optic is best checked using a laser collimator. Placed at the inlet port, adjust the grating angle until the beam is seen on a centre marked target (piece of paper etc.) at the camera port.

If everything is properly aligned the laser dot should sit on the centre of the target. 

Focusing: the slit gap can be measure in pixel and compared with the gap setting, minimum width = best focus. Normally this is actually done by measuring the reference lines, close to the target wavelength. The FWHM should be a minimum to achieve maximum R value.

HTH

Louise,

Any updates???

Ken

Hmmm

OK If your guide camera has NO built-in ST4 port (this seems to be on 100% of all the guide cameras I've seen) then yes you need another method of connecting the guide camera to the mount.

Shoestring do a similar adaptor GPUSB ( http://www.store.shoestringastronomy.com/products.htm )

Check your guide camera first - it should have the ST-4 connection. All you need is the ST-4 cable.

Hmmm

the diagram seems to show Hour Angle ( the difference between the RA on the Meridian and the RA of the object)

Ever wondered why the RA circle on the mount is movable and can be rotated and locked, whereas the Dec circle is permanently locked?????

Ths is to allow you to set the RA at the Meridian to the local Sidereal time, lock the circle. then move the RA axis to the target RA. Then move the Dec axis to the target Dec. (This is how we did GOTO in the ol' days  )

No images attached?????

The issue of "burning lenses" has come up before.

I prepared a spreadsheet of the "energy balance" across a modded PST ( and any other telescope used for solar).

The "do not exceed" energy intensity, after much discussion, seems to be around 10 Kw/m^2.

The Baader D-ERF is good at what it does, just passing 27% of the total solar energy.......

Solar ignition.zip

Not sure what you mean.....

Assuming you have a mount capable of accepting guide commands (i.e with an ST-4 guide port), all you need is a guide camera fitted to some sort of guide scope which in turn is rigidly fitted to the imaging scope and a ST-4 cable between the camera and the mount. PHD2 will take it from there......