ISIS do not merge the orders 51,52and 53 to a xxxfull.fit

[Joan Guarro Flo]

Hello Berthold and Olivier,

There is also the possibility that, (within the guide box), the input of the optical fiber and the pinhole have been decentralized. Is that possible?

Cheers, Joan.

[Olivier GARDE]

Hello Berthold and Olivier,

There is also the possibility that, (within the guide box), the input of the optical fiber and the pinhole have been decentralized. Is that possible?

Cheers, Joan.

Joan,

yes, it is a possibility, but it is also possible that one of the two fibers are defective. Personally, I had a fiber that lost more than 50% of flux after a while. (excessive curvature or stretching during telescope movement affected flux transmission through the fiber)

[Andrew Smith]

Berthold, have you tried cleaning the ends of the fibre? Even a small flecks of dust can obstruct the small fibre.

Regards Andrew

[Berthold Stober]

Hello even if I have switched in ISIS " reduce from order 32 to order 54 , ISIS do not reduce the order 54 , only at order 54! In the def_order.lst , def_line.lst and in line.lst the order 54 is defined .

What could be the reason please?
Berthold

[Berthold Stober]

ISIS reduce in my case only at order 53!!

Berthold

[Olivier GARDE]

If ISIS can't merge all orders, there is a problem on the edges of orders. You can check this by a "check3" in iSIS as on the attached image to check if ISIS detects all orders well and specially on the edge of each order. If it does go in all directions as in the example below where there has a "mustache" on 2 orders, that's could be the problem.



To remedy this, 2 solutions:
- Modify the def_order file by modifying the start and end X values of the problematic orders
- Increase the number of flat to have more flux on these orders edges.

Also check that the def_lambda file correctly overlaps the orders on each other by 5-7%.

And you will obtain this merged graph (process with the Vega spectrum I send you), here with orders from #30 to #57 (but it's difficult to have #56 and #57 orders and the nominal value is order #55)

[Berthold Stober]

Hi

I have a new fiber from shelyak now but I need 40 sec to get 30.000 ADU with a KAF 1603 with the tungsten lamp and the calibration unit from shelyak, with the old fiber I needed only 20 sec for the same flux! What could be the cause?

Berthold