ESHEL : extreme orders

[Stephane Charbonnel]

Hello,

I try to push Eshel to orders 30, 31 and 53.
In order to obtain these extreme orders, I must use a 600sec spectrum of Alpha Del instead TUNG+LED. With this last, I cannot obtain orders 30, 31 and 53 because signal is very faint (I use ISIS).
To obtain these extreme orders, I don't want always make spectra of 600sec with mag 4 stars at each time ! I would like use TUNG+LED but I must take more longer exposure. So, orders 34 to 40 could have some satured pixels. Is this a problem to have satured pixels just for order detection ?

For the moment, I haven't find Thorium lines for orders 30, 31 and 53 (Thierry has send me a list) but before trying identification, I would like to know if the information of Eshel could be used for these extreme orders (poor instrumental response for example) ?

Stephane